I have found a fix for this "Issue" : just talk to another trader and you can save like usual.
At least that's what I have found in the Druid Grove, first I talked to the halfling trader, can't save, talked to Dammon, saves working again. Also, I am running mods and such...
Hope this works for you guys.
Edit: so yeah, the issue in the Druid Grove is the Halfling trader.
This is interesting. I was having this issue with him too. On the mod page, there are others who are having issues in other acts. So I wonder how this is occurring and with what type of model. If everyone can check what merchant they were having issues with? It may be traced to an NPC model that either the mod authors can fix or traced to something that Larian may have overlook with certain models?
