Zombies, zombies, unlimited zombies, but ZOMBIES

WHHHYYYYY
I just made a new world today, and, after clearing out a few houses, doinking a few heads, the usual, I decide to kinda sit down at this cabin, then BOOM, every time I start to load corpses into the van to drive em away, atleast 5 zombies come up randomly, that's fine, but then I do the same with them, BOOM, another group, I decide to move, maybe the location was bad.
4 more houses. Is this a bug or something???? It's just unlimited zombies no matter how many I kill, my settings are so they dont respawn at all too.