Keen to do this questline as there is an energy point for it. The first quest I got was number III, a little confusing but whatever, then next day I got given number IV, okay, no problem. Then next day I got number II, so it all seems a bit random. Unsure if that was by design or a bug. However, the real problem is that now it won't give me another quest, 5 days after completing the last quest now and nothing, so I am stuck.

tl dr - its not a bug, at least support said so. What i think happens - any quest of group can pop up any day, its on players side if player can  see the quest. So if  you don't have access to today's quest - you don't see it. I didn't had any quest showing up for 2 weeks.

Thanks, will have to keep checking, no luck today.

Pretty puzzling as to why they would add this (somewhat frustrating) random mechanic to a quest chain.

Looking at BDOCodex it seems that each block of 4 quests requires completion of the previous 4 and is random, this could tale several months to complete. Very perplexing design.