Appearantly when you drive slowly enough out of the yellow pitting box after the pitting has come to an end, it doesn't end that pit-state.
If you continue to drive slowly enough then you can drive to the end of the pit area, where, if you stop, it pits you again and when you continue, stepping a bit on the gas pedal, it spams with refueling message until you get a "BLANK OVERFLOW" and you get disconnected from the server.
In single player, it just spams that refueling message until you throttle up enough to get rid of that pitting state.
here are 2 videos of it (x264 mkv):
http://mikk36.eu/web/random_shit/lfs_pit_bug.mkv (15MB) - multiplayer full length
http://mikk36.eu/web/random_shit/lfs_pit_bug_2.mkv (1MB) - single player ending