Fridu you bring what confused here . Your problem is a special but not to be discussed here generally I think. Yes, your problem has been solved by a Fresh Istall . If I had tried so immediately in your place. But in general , the problem does not solve through a Clean Install. I have changed my device 3 times and wanted to give up .
None was re manufactured from a backup!
Now I have a flawless device!
The hardware components used in the Ipad are manufactured by different companies. And somewhere the fault must lie. Many have said here and they are right!!
Displayed in this video you can see a freshly restored Air Ipad 2 with pop . Established as a new Ipad without backup.
https://www.youtube.com/watch?v=vPDScof5uCc