Last week I decided to get the Force of Nature badge for Purple Lovin'. I went Rogue and picked up the Peregrine Island mayhem mission from Lord Schweinzer, set to my usual challenge level of 0x8. The bank hero was Holo Man, but the mission didn't end after he was defeated. I know that sometimes the holograms he summons can count toward the required defeats, so I just logged off after a minute. On my next attempt, the hero was Manticore: again, the mission didn't end after he was defeated, even though I went back through the bank in search of stragglers. Then I ran the mission again: the hero was Holo Man again, and again the mission didn't end.
To try to reproduce the bug, I switched to 0x1 and ran it again. The hero was Cacophony, and the mission ended properly after she was defeated. I went back to 0x8 and tried again... and it didn't end.
Since then, I've run it about a dozen times, with several different characters. Without fail, the mission would complete after the hero defeat if set to 0x1, but not end if set to 0x8.
https://imgur.com/a/AELBcFv