AI units transferred to the headless client ignore gunshots from player/s. When the locality of the AI is transferred back to the server (or never moved in the first place) AI react correctly.
I've attached a demo mission which gives the user an addAction to change AI to the HC, please allow time for them to change (10-15 seconds). This was done in a vanilla environment, the client is the stable 1.64 release (1.64.0.138732) and so is the server.
Server launch params: -port=2320 -config=C:\arma\profiles\server.cfg -cfg=C:\arma\profiles\basic.cfg -profiles=C:\arma\profiles\server -enableHT -nosound
HC launch params: -client -connect=127.0.0.1 -password=***** -port=2320 -profiles=C:\arma\profiles\hc -cpuCount=2
Server.cfg contains the required code
localClient[] = {"127.0.0.1"}; headlessClients[] = {"127.0.0.1"};