Yeah, it’s a tough one. We do have quite a few plugins, but not iThemes Security or Wordfence. I’ll keep digging. Thanks for your help!
I don’t seem to get the error for any of those instances. It doesn’t seem to be every user that it happens to, just a few occasionally.
I’m also having this issue of feedback not submitting but not receiving any error. The feedback appears to submit just fine on our site, but it doesn’t appear in WordPress under the Rate My Post stats or within the post it was submitted on.