I replaced a fuel level sensor in a 2009 R1200GS last evening - bran new sensor & uncalibrated. Filled the tank to 5/8, and the gauge on the bike read 5/8. Filled the tank up full and the gauge read full. Fired up the bike and idled for 10 minutes, and the gauge remained reading full, as it should.
Prior to turning the key for the first time after the sensor install & with a bone dry tank, I cleared the computer (battery cables shorted).
The bike has 39,900 miles. For a short time prior to the sensor going bad, I had been transferring fuel - while riding - successfully from an auxiliary fuel cell. Early on after the sensor failure, I didn't know if doing this "on-the-fly" transferring would have been a contributing factor, but the more I think about it, I don't believe this would have any effect on the sensor itself.
If anyone has a different feeling about that, please let me know, but I think it's just a coincidence - mainly because the first few tank transfers went just fine.