I think I finally found out the real cause of this problem and after close watching the last few weeks without any problem (used to be hard reset once every two days), I would say it is actually a quick fix.
It turns out that the today timeout value most likely the problem as both PA and the standard BT icon are the today plugins. The default timeout value is 4 hours so if your phone is left untouched after this value (during night for example), there is a chance that the registry of the BT could get messed up when the plugin is awakened by the user. By setting the timeout value to maximum 12 hours, I do not have any BT problem since I made the change, and I make sure I touch the phone within the limt.
It is very easy to change it via menu (right softkey) -> Preference -> Today Setting and change the Today timeout value to 12 hours via the pull down bar. You need to make sure that your BT registry values are correct (my previous email in this thread).
Jeff