I have exactly the same problems with my setting: Amplifi 150 + Ipad Air Wifi (A1474) IOS 8.4 with the app 2.50.0 + Shortboard FBV MKII.
The bluetooth connection gets dropped for the remote app, but not for the music streaming.
So bluetooth is working but the app is not connecting with the steering of the device.
And this is regular meanwhile 90% of the time, only if I reset everything it gets back to work for one song with the downloaded settings.
So currently I play with the preset sounds of the amp.
It got more instabile with the new version of the app which was automatically downloaded.
Because of the posts I will definitely wait with the upgrade to IOS 9.02.
I hope you fix this soon.
When I got the shortboard 7 month ago everything worked and I was impresses with the flexibility. Currently the Amp is a only a quiet expensive streaming loudspeaker.
Therefore I can fullly understand the frustration of some of the others here.
Btw. one more remark it would be extremely helpful if the banks of the amplifiy would work without the app and you can only steer them via the shortboard.