The AI often moves through other Union soldiers and through walls:
http://www.youtube.com/watch?v=iKn_3WuxsIk&feature=youtu.be
http://www.youtube.com/watch?v=FMjUfQa-3VQ&feature=youtu.be
It can also pass through the column, inside buildings.
This ugly detail exists since the alpha version and still not fully fixed!

And no one wants to think about it.
BIS think only about the new DLC!
Forget about the new DLC! At first, fix the old elementary errors!
I am willing to pay for each update(if it will fix main errors!), but not for each DLС, which adds new errors.