Thanks, this was a mod security issue for editing SPPAGEBUILDER frontend.
It is great to know as I have had this issue with adding modules in SPPAGEBUILDER for a long time and just worked around it. I would add a joomla module in a column, save it and it would no longer be editable in the frontend. It is editable in the backend though.
I had my host provider check what rule was being activated, it took a few attempts but finally they found the correct rule.
Just adding this info in case anyone else has this issue.