Just curious... what enemy slot is the Lanmola in? The first? Somewhere in the middle of the list?
I think that the cause might be that Lanmolas--while loaded as a single enemy--are actually treated as multiple enemies. It might be that the Lanmola is logging each of its segments as separate beatable enemies, throwing off the screen count.
By which I mean this: Lanmola has X segments, there are 6 other enemies on screen.
The enemy screen count expects 7 enemies, but there are actually 6 + X enemies on screen. You kill one enemy.
The no return count now expects 6 enemies, but there are 5 + X enemies on screen. It kills the last enemy in the list to reduce the count, but it's still too high. It keeps removing enemies until it gets to the Lanmola, which has more segments than there are enemies on the screen. So it kills the Lanmola too, leaving the screen empty.
I'm just brainstorming here. Try switching the Lanmola to the end of the list to see if the behavior is different.
