I figured I have the same problem as I posted yesterday for another page. When I open a customizer on that page it will display correctly but as soon as I close it and load as a normal page it will make this error.
I tried disabling all plugins like I said. I did a clean WP install for this test build, and only use few plugins for max performance. I also imported Catalyst theme so maybe something got bugged in this process?
I can give you login details if you wish, it’s a test site anyways.