The enemy supply van is retreating after getting their faces torn off and, being only a Dram and a Buffalo, I only send my fighters in pursuit from the left and right. I order half to attack the Dram and half to attack the Buffalo.
But, the Dram is a decent bit faster than the Buffalo. So, when my fighters arrive from behind, the ones that are supposed to be attacking the Buffalo do so. The ones set to attack the Dram fly past the Buffalo en route, go "oh noez an enemy ship", and turn to attack it. The Dram retreats without a scratch.
It would be so nice to have a special "just go there and pour your weapons into this ship and ignore everything else" command, both for pursuits and last-stands. The Intercept command's description seems to say it should behave this way, but it doesn't seem to.