Model 3 left plugged while gone.

[JeffnReno]

We left our Model 3 plugged in on 7/5 after charging to 80%. I set the limit down to 50% before leaving it for a 4 week vacation. I got a notification that it charged for the first time last night. The strange thing is it charged well above the 50% set point. It charged back to 197 miles. It's plugged into the UMC on a 14/50 outlet. Any ideas of why it charged above the set point?