You've probably looked at these ideas, but here are some things to double-check...
Are the reel strips installed on the reel basket correctly, maybe the beginning of one of the strips was put on the reel basket at the wrong starting place?
Is the reel basket loose or slipping on the reel motor shaft so that it stops with the wrong symbol on the payline?
Are you sure you have the right award glass on the machine for the game chips installed, or that you are looking at it correctly? Can you post a photo of the machine's award glass?