If my fighter attacks a ground territory and wins can it land there or does it have to fly back to a territory that I controlled from the beginning of the turn?
Can you attach a saved game file here? Save it just before combat, and make sure you describe the behaviour in detail (ie. which battle is screwing up, which round, what the rolls were, what you think they should have been, etc.)
If your’s attacking the capital, you wouldn’t want to SBR, 'cause the IPC’s will be yours after the takeover. If attacking a non-capital IC, go ahead, as it depletes your enemy’s IPC’s.
Both moves are legal, the first just wouldn’t do you any good. :-D