I did not try 1.2.9 with iOS 10.x.x as I had first updated the ios.
I have 10/24 character slots.
I tried creating a new group with new characters and this works fine. However, now I need start the scenarios from the beginning and I don't want to do this. I had just paid for the whole campaign too.
If I can't continue my campaign, it's kind of a deal breaker for me.