The resistor-diode network is a proposed workaround for BATT to BUS leakage problem. The reason for the 1k,10k resistors is as follows:
The control circuit which shuts off the current path from Bat to Bus does not operate when Int_3V3 is lower than 80% of the Bus voltage. The added 11K resistance between INT3v3 and BUS helps prevent INT3v3 discharge faster than BUS when charger disconnect, thus preventing the possible Bat to Bus leakage issue.