When I update a page sometimes it's impossible to save the edit. I get the following error message: docserver-http: HTTP 404
It doesn't happen all the time I try to save, but only for certain pages.
The error happens when I press the save button after the dialogue where I can add a summary. When I press the close button ("Sluiten") I return to the dialogue to add a summary, but with the save button greyed out. It's also impossible to check the edits I made ("wijzigingen controleren") that also returns error 404. Trying to switch to source editing keeps hanging and never switches to source mode.
Example page where this happend: https://nl.wikipedia.org/wiki/Anna_Domino?veaction=edit
This was later attributed to interaction with local code. Thoughts and fixes are provided toward the end of the page.