At some point in my patch 7 playthrough (MacOS, for what it's worth), one of my companions (Astarion) seems to have decided not to follow me any longer, despite being grouped with the main party. If I switch to Astarion, everyone -- including my PC -- will follow him as expected. However, he doesn't follow me, and since my PC is the face character for the party, this means I have to make sure to babysit Astarion to ensure he makes it where the rest of the party goes. I've tried ungrouping and regrouping, re-arranging portraits, multiple restarts, toggling and untoggling sneak mode, etc., to no avail.

I couldn't tell if this bug has been reported, as prior searches seemed to turn up examples of folks being confused about how the grouping mechanic works. I've played other Larian games (like DOS2), so I'm familiar with the mechanic, and this is definitely a bug. I can't identify an explicit trigger, unfortunately. Oddly, Astarion is consistently the only companion who has this issue, though I have not tried e.g. leaving him at camp and taking on another follower (he's too critical to my party!).