Me being a big Pebble watch user I have noticed since the Pangu 8 Jailbreak that the connection has not been so great. I have to resync my watch about 3 times a day. By going into the Bluetooth settings on the watch and phone and delete both and repair the devices. Also some notifications would come through and some wouldn’t.
So I went Cydia and installed Pebbleprofiles and it took care of the issue for me. My watch looks to be staying paired with the phone at all times now. So if you have this problem this might be something you should look into.