Wingmen won't attack ground targets

[Juste_Milieu]

Hi all, sorry if this has been asked and answered before. When ordering my wingmen to attack ground targets (Xbox 360 version in realistic mode) instead of attacking they scatter to the four winds - has anyone else encountered this? I first noticed it on the first Battle of Britain mission where you attack German ships in the Channel, none of my wingmen would attack the ships when ordered to. Then I noticed it again in some of the Sicily missions and most recently in the Battle of the Bulge mission where you are ordered to clear the supply drop zones. I ordered my wingmen to attack and when I checked the map they had flown almost off the edges of it!

Am I doing something wrong or is this a known bug?