Hey Themeco,
I have a fresh install only with E&P Forms Builder and WP Forms Plugin installed.
Pro has the latest version 5.1.5
When both Plugins are active and I open a post to edit its content in Gutenberg I get a blank white page.
If I deactivate on or the other plugin the Gutenberg editor loads correct.
So it seems the two form plugins do have a mid-air collision. Would be great if you can checkout which plugin is causing the conflict. I can give you Admin credentials if needed. Let me know.
Best
René