Last night I went to get in the Prius and when I touched the door handle it didn't do the usual two-beep unlock. Instead it rapidly alternated between unlock/lock 4 or 5 times in the span of 5 seconds or so. I wasn't touching the "lock" spot. Lots of beeps. I couldn't even get the door all the way open because it locked again half-latched. It took a little bit to get it open. I could reproduce it at will standing there in the parking lot, but after I drove it home I haven't been able to get it to happen again. Has anybody seen that before?