2015 Volvo S60

I WAS IN STOP-AND-GO TRAFFIC ON A LEVEL SURFACE STREET. AFTER I CAME TO A STOP, THE STOP-START SYSTEM SHUT OFF THE ENGINE. WHEN I LET UP ON THE BRAKE SLIGHTLY, THE CAR STARTED TO ROLL FORWARD, BUT THE ENGINE DIDN'T START (IT NORMALLY DOES THIS). WHEN I LET UP LIGHTLY MORE AND QUICKLY USED THE ACCELERATOR, THE ENGINE FELT LIKE IT STALLED. ONCE STALLED, THE DASHBOARD SCREEN READ "PRESS START." PRESSING START DIDN'T DO ANYTHING OR PROVIDE ANY FEEDBACK, AND SUCCESSIVE ATTEMPTS DIDN'T HELP. AFTER NOT HITTING ANYTHING FOR A ~MINUTE, I FINALLY GOT FEEDBACK: THE CAR WASN'T IN PARK. AFTER PUTTING IT IN PARK FROM DRIVE, I WAS ABLE TO START IT. THIS ALL MAKES SENSE FOR A CAR WITH A MANUAL TRANSMISSION, BUT "STALLING" AN AN AUTOMATIC, THEN GETTING INCORRECT INSTRUCTIONS WAS UNNERVING. IF THE CAR HAD AN ACTUAL KEY, I PROBABLY WOULD HAVE TRIED TURNING IT OFF, FAILED, THEN REALIZED THE CAR WAS STILL IN DRIVE, BUT THE PUSH-BUTTON START DOESN'T MAKE IT CLEAR WHAT STATE THE CAR IS IN. I CAN'T REMEMBER IF I INITIALLY CAME TO A STOP OR WAS < 1MPH. I ALSO CAN'T REMEMBER IF I APPLIED THE BRAKES AS THE ENGINE STARTED TO START BACK UP, THEN LET UP ON THE BRAKES, OR IF I ONLY LET UP ON THE BRAKES ONCE.