Please provide us with the necessary steps to replicate this issue. Also, please provide us with the back end and FTP access to check on this.

Hello Mark - Greetings !!
The issue happens on submitting comment in Easyblog post as mentioned in screenshot
However - when cache cleared - then the comment is submitted in
The registered user can submit in comment, (may be because cache does not work when a user is logged in). However with guest user - this is the error as mentioned

Would it be possible to let know whats causing the same
I checked in this post - https://stackideas.com/forums/on-comment-syntaxerror-unexpected-token-i-in-json-at-position-0

having the same issue - Here Arlex Wong confirms that he is able to reproduce the issue
Am on eb 5.0.37 & j 3.6.x - dont want to update to eb

could you guide on a solution i can put in a fix at my end

thanks

1. That other thread is a different issue altogether.

2. I don't have the access to your site so I have no idea what to do here.