The same thing applies as on PC think of it like this. “Too many cooks spoil the broth”. The single handed biggest problem is to be honest is the fact that they will be fighting for processing power and ram. (That’s on android, on a PC there are low level drivers employed by AV vendors including Avast which could crash your PC on rebooting if there are two running together). I take it you have real time scanning turned on for both of them?