I’m using a first gen mini iPad and my screen turns black then back on my home screen. Everytime this happens, i get “0” attacks on battling titans, “0” points on Alliance Wars, and lose points of the odds on Raid battle.
Also when i watch videos to claim free materials/gems/etc., my screen turns white and won’t close out.
Let me know if there’s a fix. 
Firstly , this should have been posted on bugs category.
However, based on your explanation, it’s looking more like device issue, you may consider closing other background running apps on the pad when playing the game, hence making the device resources exclusively available to the game app.
If that doesn’t help, you can also contact support, via the game app.
I had to trash my first generation ipad because it could not keep up with game - it used to until over a year ago it started crashing - moved the account to galacy note and works great