Factory Sunroof Glass Re-Fitting

[stufarri 98 3 Cars]

Hi, I had to remove this from the Goodwood when it went in for paint.

 

I have had it fitted afew weeks now and have notices that whilst is slides back and forth, there are different sized gaps on each side. One side is 10mm, the other 20mm or so - for the whole length of the glass.

 

It is clearly not sitting centrally on the runners and wondered of anyone has seen this before and what causes it.

 

Thanks