It doesn’t occurat all time. It’s not just related edit a page. I can see this error sometimes. After refreshing it, the page work(Sometimes after a couple of refreshes). You can see sample screenshots below.
https://ellsekozmetik.com/errors/pnf5.png
https://ellsekozmetik.com/errors/pnf6.png
https://ellsekozmetik.com/errors/pnf7.png
https://ellsekozmetik.com/errors/pnf8.png