I have the exact same problem. I wonder why no one at BioWare has addressed this bug yet. Perhaps they just don't knoooow. Well here you go, devs, here's the low-down on the bug.
What I'm playing.
As described above by Willow_Elessidil, if a character with full focus (3 bars full) dies and gets picked up or resurrected, only one bar is restored (instead of three) and no further focus may be gained until the game is reloaded (not restarted, just any save loaded).
Can others with the problem please post your stats too to help the devs narrow this down?
