Having the same issue. Latest FW on my 150 (SN:TMA2L6401007751) and iOS on my iPad, as per Jun 2015.
When starting the app, it connects and starts syncing. After just a minute or so, the connection drops and I have to kill the app and restart it. Mostly this works, but sometimes I also have to forget the bluetooth device and repair. Very frustrating. This have been going on since I don't know when. Perhaps 6 months at least.
One thing though. Even when Amplifi app looses connection, all other apps like Spotify, Youtube or Music player streams music without interruption, so this seems to be either something with the Amplify Remote or something with Bluetooth Rx from the Amplifi 150.