The page seems to log me out too soon

I've twice now had an issue where I'm active working on writing a post and when I finally click on Publish I get a "Something went wrong" message or something to that effect. After poking around for a while I figure out that for some reason I'm no longer logged in. 

I am making sure the stay logged in is checked before I log in so something appears to not be working correctly. If the stay logged in is working as designed can you please extend the time out to something like 2 hours so we don't get surprises?

Thank you