I found I couldn't use Mass Edit to change the Alliance property of multiple NPC tokens in the PF2e system (found in Configure > Alliance of the NPC Actor sheet). Note that it is possible to do so for PC's with Mass-Actor EDIT > System > Details > Main > Alliance
EDIT: I just discovered that the issue is only with NPC's with Alliance set to Neutral. After I did some research I think this may be due to the fact that Neutral sets actor.alliance to null rather than a string (e.g.: Party = "party", Opposition = "opposition")
I found I couldn't use Mass Edit to change the Alliance property of multiple NPC tokens in the PF2e system (found in Configure > Alliance of the NPC Actor sheet). Note that it is possible to do so for PC's with Mass-Actor EDIT > System > Details > Main > Alliance
EDIT: I just discovered that the issue is only with NPC's with Alliance set to Neutral. After I did some research I think this may be due to the fact that Neutral sets
actor.alliancetonullrather than a string (e.g.: Party ="party", Opposition ="opposition")