Originally posted by Ataxio:

This would drive me nuts if it was happening to me, but its not at all. I have no idea why.

Not exactly a solution but, you could have some wolves roaming around on property which in theory would deal with anything that gets in.

I did use this method, but the wolves were cleaving my structures (doing way more damage than the monster would have). Also they were eating their prey and breeding which trashed my fps over time.

As for the other post and reddit thread that a couple others mentioned here, the workbench clearly didn't stop spawning for me in the first place, which is why I'm not banking on that.