Would love to know what exactly this "mechanic" is and how you trigger it. Been grinding there for over 20 hours now and have not seen a single alert or message about "alert levels".

Same, I spent about 10 hours at this spot at various places and didn't get any sign of this mechanic working.

https://grumpygreen.cricket/elvia-biraghi/

Gives general idea about stages. I saw yellow beacons (some player) who was triggering alerts. I seemed to be not strong enough? I had some triggers at Altar and Fogans.

Thanks for sharing the guide link. According to it, alert levels are triggered when 2 or more players are present in the area. So far I always grinded alone which would explain I haven't seen any alert.

Hmm, that spot has been pretty busy the whole time I've been there. Never been alone besides a couple hours at like 4am. But yeah, I never got alerts while other people there or alone. Besides, it's advertised as a solo grind spot, if it requires more than one person to trigger the mechanic that's super dumb.