I do have edited xmls and WF maps, could this cause problems? Anyway, this is really curious. The freeze/crash seems to occur when the 'if' line cannot be executed. Now I did something like this:

For factions whose members can't be captured, do we need to set <fCanBeCaptured> to 0, or no need to define it at all in "CivGroupNames.xml" unless they are capture-able? Because in my mod "CivGroupNames.xml" <fCanBeCaptured> isn't set anywhere. Whilst in 1.13 variant, it looks like every faction with AddToBattle set to 1 has it.