All info as requested for an out of memory crash, no idea as to why.
BUG repeatable from saved game(02-Cant attack all). I was attacking a stack of enemy units, and I could only attack one of them each time, after combat I was superimposed on top of them and they would then move way, wash-rinse-repeat.
Found that If I sent a single guy after them, then left him on top of them, the rest of my units would then attack them as a whole.