Error message "Bluetooth stack is unstable......" what is this?

Hi Has anyone seen this before and what has caused it.It came up on Sony Experia E and the Beacon appears ok from other devices?

Whole message

Bluetooth stack is unstable (switching on and off frequently) Please contact your device manager for details

Many thanks

This is a message our Android app shows when it detects your Bluetooth is crashing when detecting beacons … we’ll try to find an Experia E and see what might be going on, but usually, this simply indicates some problem with your smartphone’s Bluetooth LE stack, so there might be nothing we can do about it.

Thanks, at least I know where the message came from,we thought it was your app. We did have several apps using bluetooth running but we’d not seen that message and everything else appeared to be working.

I’ll post here if happens again and try and get more details last time it was in the middle of a demo so I had to move on.