Brought it into the dealers and they replaced the "brake control unit" and it has not happened again so far. Once the guy there heard what was happening and the age of the car (2014), he suggested this immediately so it may be starting to come through as a known issue.

Did you ever find an answer as to why this was happening? Same thing happened to me today. Not sure the parking brake actually kicked in properly when the light was flashing as I did not feel the slight jump in the car when the brake activates but the car didn't move. When I restarted all was back t...