Question about units joining battle

[lester]

Why is it that in older savegames I was able to attack Marinvoka from both sides like so (https://imgur.com/a/SR4pvce), but in new savegames now I attack with the same units the same positions, but now the attack looks like this (https://imgur.com/a/lMTdXFH).

Was there an update that changed this or am I doing something different?

Any help would appreciated.