I've encountered this with unmodded 1.16.2 Minecraft on Linux (Fedora 32). Seed 077401122477023, coordinates [-254, 64, 299], oceanside plains village. Structure is a house on top of a deep pit.
Confirmed in 20w14a
Seed: 2833266223617890175
See MC-158238 (Too many iron golems in single village). I have six or seven iron golems for a village of 12 or 13 villagers.
There's 12 or 13 villagers.
I can't seem to reproduce the problem when I regenerate the same world with 1.16.2