Ok so it turns out custom content wasn't at fault. After a lot of testing I've figured out that only sims with evil and mean traits can kick gnomes. Pretty sure this wasn't true last year but it must have happened in an update.
Move your Mods folder to the Desktop and delete localthumbcache.package. Then test the game
If it works now check for updates to your Mods and CC. Add it back a little at a time while testing until you have found all that are broken.
Thanks. I did that and it didn't make any difference. Then I tried to make a new save without custom content and then the interaction was back, but once it was broken again it wouldn't come back. Weird issue. I'll try to figure out exactly what is doing it.
Ok so it turns out custom content wasn't at fault. After a lot of testing I've figured out that only sims with evil and mean traits can kick gnomes. Pretty sure this wasn't true last year but it must have happened in an update.
