[Gatts]

Chup1n

Looks like the "reinstall" solution worked fine for you.

Here is the step by step reinstall workaround:

backup saves (is not 100% neccessary, but you should make sure to not tick the checkbox at "remove saves" when uninstalling)

Install game anew

check if your saves are intact

load your upper hadar save, but first move out of the area -> to lower hadar and back... now it should work perfectly (without running trough the game from the start)