Sometimes as I'm traveling I find items dropped from animals just sitting around; raw beef, chicken, feathers, etc. Unless there's some mechanic I don't know about, with hostile mobs killing animals or something, I think something is going wrong with spawning.

The reason I think it's this plugin is that I once saw a group of pillagers where two of them were taking damage and died. This makes me think it could be a bug of the Animal Overcrowding Control setting (currently 10). The others didn't actually move until I got quite close to them, so this is potentially interacting with the entity-activation-range Spigot setting?

I haven't played Minecraft for a while so hopefully I've reported right and this isn't a bug or mechanic in vanilla

Ah ok, seems very unlikely it's this plugin then. My next culprit is the Modern Beta world-gen data pack, maybe that has defined the spawns weirdly. Thanks

there is a debug option you can enable, but other than that don't really know what else. include config and /version extrahardmode when you get more info.

Animal Overcrowding Control only affects Animals and clears drops if an Animal dies due to this.