Under certain conditions (the exact details of which I haven't quite worked out yet) the talisman conditions for some levels cannot be edited.
I'll update with more details if I can figure out exactly what's going on, but I've attached the level I found this on.
The talisman "Optimization Lv. 2" was intended to have a limit of 3 bashers, but was saved with no requirements. I didn't notice this when the v9 update was first released (it was a contest level). When I noticed, I tried to fix it through the editor, assuming it was an oversight on my part, only to find that I couldn't change it. I thought that it might be due to its similarity to the talisman "Optimization Lv. 1" (limit 4 bashers), so I tried removing one of them, and the delete button didn't do anything.
Manually editing the talismans in a text editor worked as expected.