RZ67 back has light bar on fotos

Well i thought it was 120 film back #1 that was making a white vertical line in several pics of the 10 (but not all).
Now got vacation pix back and Back #2 fotos have that same line, same spot.
Is it my RZ?
If i knew how to UL a pic here it would be clearer but anyone get this white line thru a 120 filmback? thanks
ez

I had the same problem on my RB.

Finally figured out that it happened when the dark slide was inserted or removed.

Fresh seals/foam will help.

I now protect the camera from light when I move the dark slide and I do my best only to move the dark slide when I have to.

Thanks. fresh foam and seals on the backs i assume? Where can i get those?