Can't add a policy to an authorization server

It’s been a while since I configured my first API & auth server. Today I’m trying to create a new auth server an apply a default all-clients policy. I have other auth servers configured similarly, but now I’m getting:

There’s no other indication of what the error is. Any ideas?

Never mind. I just tried it again and it worked. Weird. Did something change today?

But now I’m getting the same error when adding a rule to the policy!