I definitely notice getting logged out more on derpi on mobile, and after I haven’t used it for a while. I also use google chrome on both windows and android. It keeps the username and password saved for filling it in the box, and it does it regardless of ticking to stay logged in. But now that you bring that up, I think it is a lot more down to just the browsers doing stuff rather than derpi. I’ve even had pony town have me suddenly logged out, as well as Reddit. Not every site does it, but every site does work differently. Or perhaps the browser just remembers some websites as being important and never deletes data from. Either way, it’s something easy to deal with, only takes like a few seconds to log back in and be back to where you are as long as it remembers the password and username.