Block Editor Error Message – invalid JSON response

Hello,

I’m having trouble setting up an FAQs page using the block editor (Gutenberg). I keep receiving the message
“Updating failed. Error message: The response is not a valid JSON response.”
Once or twice I also received a message telling me that the block editor required JavaScript and to enable it in my browser settings. As I’ve been using the block editor with no errors for some time (on the same browser), this could not be an issue. Of course I did check the settings in my browser. Not sure why, but I am no longer seeing this message.

However, when I view the live FAQs page, the changes that I made DID go through.
This is a confusing series of events…

After looking into the matter, I decided to start the page over from scratch and see if this was happening on any new page, or if it was related to specific content on the page. As it so happens, I only receive the error messages after applying the “Submit FAQs Block”. As I said, regardless of the error messages, the Submit FAQs section DOES appear correctly on the live page…

Has anyone experienced a similar issue?

Thanks,
Matt