It has been there a bit, I put them in loose formation they they bunch up and loose formation doesn't work and they get bugged, I have to put them in shield wall then loose formation to get them back in loose formation. and TW let me know Ill get ya video of it,, for some reason they leave loose formation and won't go back unless you use a different formation first.
I have had that same issue, only thing is i would try and put them in the line formation and back to loose and they would still be in that tight 5 row and column formation after go back to loose. Maybe ill try shield wall and see if that works for myself also.
looks to me that your archers started moving immediately after you issued your footment to attack. before you even sent your cavalry. and of course the shield wall + lose formation just fudged it more. i always always drag my troops. if i have a lot of them i get high ground first. it's a pain without rts mod sometimes