For running J!5.1 you must https://fabrikar.com/forums/index.php?wiki/update-from-github/ or include the new file manually https://fabrikar.com/forums/index.php?threads/joomla-5-1-and-fabrik-cannot-find-files-error.54473/post-285151 See also Announcements
Please see our announcement here.
I updated in the wee early hours on the 16th.Are you running the latest Git? There have been some fixes addressing "debounce"
To answer your question... Yes, as a matter of fact, there is a form module on the page. Sorry, I just realized that. So what does that mean?AJAXified?
Any form modules on the page?
Can I see the page?
-- hugh