I use the app on my phone & it logs me out right away but maybe it's because I log in & out through Facebook.

I don't know of any log outs on my phone app. But when I log in I the app connects to my Facebook account. When I'm done , I just swipe it up to close the app.

I use this app on my tablet and just close it down and don't really know how to log out but after sometime it will log out anyway.
I've got it set up that it logs me in when I start the app so don't have to put all my details in each time as live on my own.
Maybe not good idea if you got family.