Battery voltage drop

Some weird numbers today. Granted it wasn't after the haul home but after I had stopped and grabbed dinner.

12.37v at rest
12.86v at high idle (it wouldn't go any higher than this)
10.89v ungrounded at high idle
2.2mv grounded at high idle

do you think the numbers are this way because i let the car rest instead of just taking a sampling directly after my commute?