Tracking ink on 8050

[mcbrides printing]

While printing 11 x 17 in Black (grayscale) I am getting tracking of toner about 3/4 inch down the 17 side.
I tried printing a sheet of almost blank 11 x 8.5 paper. After about 12 sheets it went away.
When I restarted the 11 x 17 sheet the tracking started again. Any suggestions

[RRodgers]

Can you post a sample?

[Elle]

damage to the heat roller would be my guess, missin a lil teflon maybe. is it reprint or just smudges? samples are fun

[mcbrides printing]

The smearing is like a pull roller that is offsetting the image on the reverse side

[Coptech]

J have seen on thicker stocks that resist the buckle at the registration where there are 2 marks where the prereg rolles skid on the backside of rhe paper but that is farther than 3/4" and there are 2 marks.
I am trying to understand where the marks are by description. If they are the same distance in referance to the front or rear of the mahine vs. the direction of paper travel, I too, am leaning towards fusing roller coating. You didn't say whether the print job was single sided or duplexed, copy face down, or straight out exit.