TLDR: Cleared Crossroads pretty early into Act 2 until bug reoccurred at Crossroads’ final boss, which I then left until before point of no return (just the boss and 2 altars, kept Crossroads cleared). My Lost Ages trigger happened prior to Act 2, went along with it, but bug was resolved after intro to Act 2.
I attempted to clear Crossroads and Regrets after Volkarin and Taash recruitment before Weisshaupt. Act 2 table argument scene resolved my bug. Attempted to clear all again from this point in fear of reoccurrence. Reoccurrence happened at the end of Crossroads quest with Revenant Dragon, which was done before starting Something Wrong MSQ with the Wardens (only a half step into the chapter). I tried to complete the Regrets and thought it was a bug that I couldn’t view them at the Lighthouse; talking to the Inquisitor in Shades of the Blight (the other half of said chapter), was the unlock for that btw.
Also here to report I have completed the game without further issues. Though if this bug persisted through the final moments I can see one specific part that could really break the ending progression really bad with all the emotions spiraling around. Thankfully, no one seems to have reported this since I assume the ending quest lines are its own instances curated to be as clean as possible.
Bellara’s achievement was bugged for me and is my final achievement. (Anyone have it unlocked and a save before the unlock for me to borrow to grab the achievement? Pretty please?) For this one, I can only assume it is related to romancing her. No other factor could explain it for me. And she was there in the pre-ending cos i chose someone else to disarm the wards. So that isnt the problem and scene was seen.