All : Infantry slow to reinforce, sometimes not at all. This is caused by multiple things : Pop-capped, Crewing a team weapon (thereby splitting the squad), Conscript Merge (also splitting the squad), Production queue too long (reinforcements have the same queue as building a squad, so if it wants to build a squad first reinforcements have to wait. Problem is if it's pop-capped and wants to build a squad)
All : AT guns are not reinforcing (except Raketenwerfer). This is because somehow Relic decided to use vehicle tactics on AT guns. Also see above on crewing. Finish healing tactics should take care of this but it's not reliable.
All : Team weapons that have been crewed with a different squad will retain their squad's abilities.
All : Infantry not retreating. One of the reasons is because they wanted to use an ability like grenades first. Also see splitting squads above. Also infantry won't retreat if they can't reinforce/pop capped (weird, but it is true).
All : Split squads HP checks do not return the correct HP. So even in editor when you specifically tell them to do something when HP < x they will not do it if they're split by recrewing or merging.

Soviets : Sometimes fail to place Support Weapon Kampaneya building in specific slots of maps. There is no solution to this. This is due to the building having an elongated shape.
Wehrmacht : Sometimes fail to place Infanterie Kompanie building in specific slots of maps. Again no solution. This is due to the building having an elongated shape.
USF : Cannot use Ambulance (work around stay still in base).Cannot move Pack Howitzer.
OKW : Sometimes sWS truck is idle for prolonged periods or even fail to place the buildings (workaround is in place). Builds a sWS truck while already having all three buildings. This occurs because Relic's code of preventing a sWS truck from being built requires all three buildings to be done, but if the buildings are still being built you can actually build another sWS truck in the meantime.