My sister had my oil changed and I believe they overfilled the transmission fluid. I am meticulous about my fluids and I am sure it was not overfilled when I lent her the car. It looks to be roughly 1 quart over the upper full mark on the dipstick. Transmission seems to be shifting fine. I was considering siphoning out just enough fluid to bring it down to the correct level.
Should I be concerned??

 

A quart is probably pushing it. I would drain it off.