I have an iPad Air and am on my 4th Zagg keyboard in one year. First two were issues with the hinges. The last couple have been about this Bluetooth problem. I don't understand why the problem continues. The first keyboards, with bad hinges, seemed to keep the Bluetooth connection going all the time. I never had to reconnect. Now, it seems I have gotten use to going to the "Settings" app and turning Bluetooth off and then on again to re-pair.
I too have heard that it's the iPad, not the Zagg. But frankly, I think that's horse manure. There have been more than a couple of OS updates on the iPad since this problem started. I have a friend who dumped his Zagg and bought a "Clamshell." He doesn't have any problems what-so-ever. But, his keyboard in not back-lit.
The conclusion I've come to is that Zagg makes a pretty good keyboard. They just need to get to the bottom of this connectivity issue and not just "Blame" Apple. Something isn't right. Zagg's customer service is 2nd to none. They have been "No questions asked," when I want a replacement. They have spent four times as much money as they have made on this keyboard, just replacing them all the time. So, it seems inconsistent that they wouldn't get more serious about this problem.
Maybe I am wrong. But, I think it's a problem with the Zagg keyboard. But, until I find a better one or there is a fix for this, I will just expect to re-start Bluetooth services a couple time a day.