It's a pretty gamebreaking bug IF it is a bug, and has not been patched despite there being what, 4 patches now?
I played and beat this game 2-3 patches ago, haven't touched it yet until it gets fixed, but if this "problem" is still here like OP claims, either Larian is terrible at patching huge bugs like completely removing your turn in a turn based game where each turn counts or it's a design choice.
I can't tell you what it is, I had so many bugs during my playthrough with a SO that we didn't even know which was intentional or what was a bug. (I looked on wiki and apparently we missed huge parts and sections in quest bc NPCs didn't show up where they were supposed too, and other quest stuff breaking, lolwut).
