I've not encountered that specifically, unless I travel somewhere with a character that others can't follow (such as sneaking into the kid's area with a halfling character). Can't offer any advice sorry.
But, since that's a new one to me, if you can spare the time, I'd recommend submitting your save file with a description of what's happening and how to replicate the issue, to Larian's bug form directly (
https://larian.com/support/baldur-s-gate-3#modal)
