I have BT problem on my K750i !
Sometimes BT doesn't work. The symptoms are:
1) Can't find other devices, while searching BT icon with blue arrows doesn't blink to usual icon.
2) At the end of searching doesn't show the error popup, just exits to previous menu.
3) There's a 15-sec delay, when I try to turn BT off.

And sometimes it works properly. What's the matter?
The phone is: K750i CID36 (flashed from R1BA003 to R1DB001). I've opened the phone, cleaned antenna's contacts, they're normal.
Thanx in advance!