Just hired NPC.  Moved him to my city, first turn he arrives in city it says he has 18/35 h.p.. Rested him for a turn, still says 18/35.  After a couple of more turns of his health not going up on the small round portrait (stayted at 18/35) I looked and the information beneath vitals (on left side of information bar) and it  was correct, it displayed 33/35.  So hovering over the small round portrait is not updating the correct data. 

Edit: About 20 turns later half of the unit icons were blank (black) circles (out of a dozen).  Tabbing out of the game and back in was the only way to fix this.