Actually, I'm wrong about this, it was a dedicated server issue. If you're looking to get forage zones working on your dedicated, regenerate the zones by stopping the server, deleting map_zones.bin in your zomboid\saves\<servername> folder, and start the server again.

In relation to forage zones - is there any way of removing all those custom rocks from the foraging spawns?
It making finding normal rocks very difficult.

dude pls tag your jump scares lmao this had me so worried for a second. i was really enjoying a diff custom map, Cherbourg until i found out that there's no foraging zones assigned anywhere, so a long term survival build is just impossible on that map. looking so forward to trying this out though