Grey Tank Level Changed after Powerwashing

[Maurerrl]

I have a 2016 Minnie Winnie that I just had winterized. When I parked it for the season the grey water tank was showing empty. I decided to power wash it since I got a new powerwasher for Christmas and it was quite dirty especially on the roof. After I was done I noticed the grey water tank is reading 1/3 full. Did I maybe screw up one of the sensors from the Powerwashing? I don't think any water got in the tank itself because I pulled the cap and a couple ounces of antifreeze dribbled out but no water. Can you affect the sensors by cleaning them on the outside? Any thoughts on what I may have messed up would be greatly appreciated.