Game center makes me sign in everytime I play a game

This used to not happen. I'm really unsure of what triggered it. When I used to play Clash of Clans or most other apps that used game center as soon as I launched the app, shortly after a banner would pop up and it would say "_vo_ signed in." Now this no longer happens. I will sit in the app for a while and then a game center prompt will appear covering my whole screen, and it will urge me to sign in.

I can now choose to sign in or cancel the process and return to what I was doing. If I choose to sign in, it will either load for a redicoulously irrational amount of time or finish signing in and return to the game. Now not only is this annoying because I have to do it every time, but going through the process doesn't even do anything. I can't even see any of my game center friends, which I could view prior to this problem occuring. I have re signed in to game center through the settings and I've tried launching the desired apps from the game center app, but none of the above seem to solve the problem. Please help me. It's annoying and I'd like to see my game center friends on this new 'Boom Beach' game lol.