Every time I want to save a page on Hungarian Wikipedia, I get the error "We could not process your edit due to a loss of session data." This repeats every time I don't click on the save button within circa two seconds after the last error page load (in fact, this is not enough to find the button and click on it, I can do this only with the access key). This bug means that I have to wait until the first error message appears and can't continue editing on another tab. Firefox 50.1.0, Windows 7.
Oops, nope. It works now, thanks! (N.B. Have I added the right tag? I was not sure how to classify this "mysterious error". What should I do if something like this happens again – after logging out and in?)
Have I added the right tag?
@Tacsipacsi When in doubt, give no tags, and it will be triaged for you. You will also attract more attention if it is not tagged (while if it is tagged, people will assume it is being handled). While anything can be operations, it is not obvious for contributors unless things fully down, it normally takes someone familiar with the code to send it to us. Operations is normally "server work", which it does not affect users unless things go very wrong. In your case I might have send it to the Editing department as they may be familiar with similar issues, on edit.
What should I do if something like this happens again
The key thing is repeating your error and debugging it. I tried editing myself and saw I had no problem, so maybe only you had affected by those problems. Normally I would ask for more information, specifically your user name, the url you were trying to access/edit and the time the last error happened- we have logs and if it is server side we can check the code failing. Also if there were more people affected by this. Because it can be anything on client side (brower) or server side, the first thing is to discard the browser is not affected/in a weird state, so I asked to log in again (maybe session got invalidated or corrupt on your browser). If it happens again, we would reopen this ticket and keep investigating. Sessions are an important issue that prevents contributors from helping, and we take those seriously.