Was this a bug, or did I mess up the order? (split attack)

Replay #18447770 at 11:30; I used the split-attack command well in advance, but the bombers just ignored everything on the first several passes. It wasn't until I made single target attacks that they finally worked. I have never needed to ground fire a split. Even when one of the targets is gone before I arrive, they automatically go after the rest. Any info is appreciated.

I think you mixed up the hotkeys "spread attack" and "spread move" in the heat of the battle, - or tried to fix it in the middle of the attack, which confused the units.

Next time, just abort every command with ESC and redo the key spread attack to be sure.