Three notes on that:

1. The 1:30hr drop chance is not with 0 drop buffs, but with 100% drop buffs. Your non buffed rate would thus be half of what you calculated, aka 1/3 only, leading in the end to a chance of about 0.01% (which is still extremely small, but also about the same chance as hitting PEN FG armors, and that has happened multiple times in game already).

Drop chances in BDO can be extremely low, like 0.0005% for the elten piece. And yet, many adventurers have it, as any chance above 0 converges towards 1 if enough repetitions are executed. Given the amount of people grinding Blood Wolves, it is not entirely unthinkable that a chance event with only 0.01% does actually happen to someone (actually, if we state it in a different way, it happens to every 1 person out of 10000).

If we were talking about the 0.00000077% chance mentioned in your post it would be far more unthinkable yes, but since you did not notice the garmoth averages are stated with 100% drop chance buffs applied by default, we are talking about much more realistic numbers.

2. The droprate of Kagtunak is very much dependent on the speed of clears, not time spent at the spot, so we'd have to know your average trash / hr, and then break down the droprate per trash to get a more accurate result.

3. The kagtunak droprate is far more likely to drop from certain mobs with a much longer spawn period than normal mobs (0.2% and 0.5% compared to 0.005%), which will lead to an inequal distribution of drop chance of kagtunak over a grind period (e.g. frenzied kagtum will be up more likely at the beginning of the grind, leading to a much higher chance to get within the first hour compared to a multi hour session's per hour chance)

NCSoft was guilty of this also.  They messed up by having some trivial enhancements show 90% success rate so you could do enough of them to be confident in the results.  Then when you failed multiple times in a row you could just laugh at the absurdity.  You could rely on constant failing while the tool tip showed 90% or even higher success rate.

The best part is they messed up so bad you could achieve statistical impossibilies on a regular basis.  Which also brought concerns to what important enchants chances actually where.

I didnt read all 9 pages but I think people are being quite paranoid. If RNG is dependent on how much money you spend, then how come a player liek me who has spent less money in this game than probably 90% of players has experienced fairly normal RNG in general?  Now to be fair my RNG is mostly drops related since i don'T enhance outside of easy enhancements for money (or like tuvala...) Stilll though If i think of recent enhancements, I so far have not failed one debo Duo enhance and seeing as they are just above 50% chance and that i made seven (to sell) you could say that's considerably lucky. It's not exactly 50-50 so the comparison is not entirely apt, but throw a quarter 7 times and see how long before you get seven heads or seven tails in a row.  It will happen some time, but it's rare. And yet i've not spent one penny in the game in months (five I think). 

Luck is luck, sometimes it's on your side, sometimes it's not. Things will even out in the long run 

Anyway I guess There's only an illegal element to doing this, meanign BDO having a dynamic RNG, if it could be proven this led people to spend more actual money on the game. It's hard for me to judge if that's the case because I buy nothing otuside of value packs (not anymore anyway as I have everything else i may ever have wanted that is not buyable on MP) But i guess people who buy costumes for crons, well if they fail enhancements more than they should because of dynamic RNG, then yeah they would be spending more real money in the game.

i'm not too concerned personally as in my own personal experience  of the game (i've been playing daily for 7 years) i've not witnessed anything that was so incredibly wildly out of the ordinary odds wise.. And if it ever was, it evened out in the long run.  Like somtimes you WILL be in the 1% unluckiest people and others in the 1% luckiest. A guy today told me they got the nol with one chest. It took me 94 (and about 199 hours more than it took them). And i wasn't even in the unlucky 1%, i was only a bit outside of the norm. 4% of people will need 300 chests. It could be you. It certainly will need to be somebody anyway.

Statistical analysis is my bread and butter work, I can tell you that some things in game are perfectly reliable for their known chance/rate... Example, Base/Upgrade output Recipe Proc Rates are so stable that for anything over a dozen crafts, you might as well just use the multiplier (side products with their much lower odds and complications can seem a lot spikier/irregular, but they're also pretty reliable if your sample size is high enough)

On the other hand I can ALSO tell you at least one ingame system outright lies to about your chances (if you want to waste the time, run numbers on season tuvalla accessory enhancement, pretty sure the actual rolls are being done with the same base chances and FS values as armor). Does anyone care? No, because it's probably just a bug, and season throws time-filled black stone at you like rice at a wedding, but it tells you something important... DISPLAYED values are not pulled directly from USED values, so you can't be sure unless you actually test

And yeah the game DOES have some sneaky/underhanded manipulationns of odds, Bad published numbers, and display/calculation bugs **... examples of each can be found in the Pets Skills learn chances.... there's 4 different sets of base learn chances (not just the two listed on the site), some of the listed ones are wrong, others are missinng. The learn chance UI has a bug for some skill patterns where more than one skill would be learned and shouldn't be trusted (TBH it shouldn't be trusted even without the bug, because they way they add rates is VERY misleading at best). It also gives a hidden PERMANENT bonus to the Karma skill learn chance after the first skill is learned, as if you used 4x skill change coupons on Karma Boost, and while the skill change is a flat percentage roll, Tier up / Skill Learn gives a hidden (temporary) bonus from the last skill in the list that already learned to whatever skill is after ANY skill already learned (Not sure if that's a bug, where they meant to just add learned skill chance to the next skill, or they just changed their mind while making the system). The end effect of which is higher chances on Karma skills that few want, some skills are only likely to show up on some pets, and some sets of skills are almost impossible to roll in to

is that enough to trigger legal scruntiny? Probably not... if it were more direct and situational, rather than automated and general, someone in the gov might care.... but YOU reading this should at least be aware of it

**: CMA Disclaimer:
None of what I posted requires anything more than reading the in-game displays, using the ingame systems, writing down the results, and a doing a little math.
ETA:
I don't pretend to knonw what the intent behind any of the mentioned chance variations above are. Whether they're honest bugs, poor communication, or nefarious, I don't know, so I can't say.

At a higher level that's not how things work in the real world.  Business's will do a lot of shady tactics, but your accessment is just wrong.

Those practices would be in violation of many laws across several countries.  A business does not get to just ignore all laws and anything goes because the Internet says so.

Educate Yourself:

False advertising is the act of publishing, transmitting, distributing, or otherwise publicly circulating an advertisement containing a false claim, or statement, made intentionally (or recklessly) to promote the sale of property, goods, or services.^[3] A false advertisement can be classified as deceptive if the advertiser deliberately misleads the consumer, rather than making an unintentional mistake. A number of governments use regulations or other laws and methods to limit false advertising.

Well, I'd like them to step up and verify as well. However, innocent until proven guilty and I've failed 90% chances several times in a row before. I am certain that your TET Tungrads are definitely way lower than that so I don't think that that's indicating PA being guilty. I mean, 90% chance and yet failing 9 times in a row can still happen. It is RNG afterall. 

So then, based on this. If no one buys outfits and sells them for silver because the community is labelling them as dumb. How will every F2P player get the crons to upgrade their gear? Then the game would literally translate to P2W because you can't get crons at a reasonable price anymore unless you spend actual money.

Even if they don't sell the outfits but use the crons themselves, spending money on the cash shop does keep the game afloat. Who the heck will pay for the servers to keep the game running otherwise? You all do realize that people who spend money on the cash shop also effectively pay for us who get to play the game for free? And you're calling those same people dumb. 

There were this streamer 'Salt' he enhanced thousands of of accessories and I do believe his RNG at the long run almost completely matched the chance percentages. Same with the other enhancer streamer ffs I forgot his name.