This happened to me today, but then seemed to fix itself. Here's what I did:
I got the error while an attempting to change the Page Title, Name, and Slug of a collection.
I tried again but left the Slug the same, and that time it successfully updated.
Just for the heck of it, I then tried one more time to update the Slug, and for whatever reason, it successfully updated. Worth a shot to try repeating those steps if you're seeing this error, even though I have no idea why it worked.