Respawning & Big Enemies falling out of Bounds (Enemy Randomizer)

I don't know how to name this, but if it weren't jsut SFM (child), that might be a bit more crucial.
In the Randomizer I seem to have Dark Link at SFM (Child) which of course replaced one of the deku scrubs.
I hit him like twice, but you know, he respawns after each hit. Now however on the second hit, I could hear him fall down. Before I heard him swim, which was new, but possible. But falling would have meant, that he might have phased through the spawn coordinates of the deku scrub?
They might be a bit lower than for a normal enemy, and so he simply vanished through the ground, never returning.
He also was not really dead either, as the music kept on playing, despite him not being close at all. Or.. anywhere

EDIT:
I also noticed something similar in the spirit Temple (child) where a Stalfos would simply run out of bounds. (walked past the early steps, you crawl out) However since I am supposed to kill all enemies, I cannot do that any more really. Plus, this is also blocked off by there being a withered deku baba, which will never fully die