When clicking on the "Edit" link on any post, the resulting URL returns 404.

I've noticed it on SuperUser (trying to edit my [question](https://superuser.com/questions/1155405/is-there-a-windows-10-privacy-checklist)) but it also happens on [this very site](https://meta.stackexchange.com/questions/117919/moderator-tools-links-return-404-page-not-found-instead-of-unauthorized) as well, so it looks like it's a network-wide issue.

My user-agent was set to `Linux` (that is, the plain string "Linux") and it looks like that was causing the problem (ironically, I had to do this to test a site that would behave differently based on user-agent, and it looks like I found a bug here as well!)

I'd like to know why the user-agent has any incidence on whether editing is allowed (especially given that it allowed me to login and post a new question just fine) and would like to see this fixed, even though I do agree it's a low priority issue.

Regards.