Truth Quest DLC bugged in a good way

I just finished the story of Truth Quest and had the achievements for 100% the new island, do all objectives in TQ, complete all time trials, and kill all questers. I went to the new island and mopped everything up and got the 100% completion achievement for that area. Upon fast traveling back to the base game area, the other 3 achievements popped straight away. Dunno what caused it, but maybe fast travel and mop up the dlc island straight after the atomic leviathon fight.

Just posted about this in one of the solution comments because I didn't see this first, but the same exact thing happened to me! Wonder if the requirements changed or it just glitches if you do it in the exact same way we did.

Are the Xbox achievements still bugged for the Truth Quest DLC? I thought I 100%'d the expansion, including time trials and the final boss but I still haven't seen several Achievements trigger.

Maybe I'm missing something or is this a glitch that hasn't been fixed?

Just worked for me. 3 achievements (2 of which I did not earn IMO) popped after 100% Plover Island > Main Land,