[Raapys]

No, if you do it in tactical combat you'll get a message as soon as the ship reaches the planet that your troops have been deployed and that ground combat will start *next* turn.

At any rate, the presence of the fighters is the only explanation I can see as to why it might get 'bugged'. But then again, I'm not really sure how one is supposed to use fighters in ground combat; if they're just supposed to be in the same hex, or if they're supposed to be part of the cargo drop like yours.