These behaviours are a bit annoying because I am sure we checked 10, 100 times these kind of fight.
We had a grid with a several dozens of type INF vs INF fight (line, column, skirmisher, strength (<,=,>, 1 to 6 batallions).. and I can say all was very good...
I believe a thing is broken in the 3D engine and I didn't spend time to fix this issue. So, I have to re-do the tests in order to definitively fix these behaviours. Just a few patience...
JMM