I checked the CVC. You must be in the bike lane except to pass, prepare to turn left, or avoid debris or hazardous conditions unless you are operating at the normal speed of traffic.
If you were pulled over and pointed back and said "That car was about to open their door, I left the bike lane" you should not be ticketed. Two cyclists riding side by side such that the left chatting would not fit this protocol. I'm not sure I want to fight for my right to have leisurely conversations in the middle of the road.