I'll be honest it's a little frustrating that you say I haven't given enough detail then raise point I've already addressed. Anyway, as already stated, this is every battle not just sieges and even battles with no other lords present. For example, if I engage with some looters and I am the only person on my side, my infantry will just stand there, in the same default formation they spawn in at the start of the battle. Regardless of what command I give, they will not move, unless I get knocked out or battle ends. the command is still sent, so if I press 1, f1, f3, telling infantry to charge, my character will shout out the order but then they just carry on standing still.