Jonathan
Do you mean the ruckbag with the chair that slips in between your back and the bag?
If so, then no - I don't have the same problem.
Have you got the chair facing the right way? The canvas side should be on your back whilst the legs and exposed frame of the chair should be against the bag.
Are you using the right chair? As far as I can recall, it ONLY takes the Roving and Supalight chairs
Are you using the right bag? A lot of their bags are rather confusingly named, and some of them look very similar in picture form. I think it's only the Roving and Compact ruckbags that take chairs - none of their other bags do.
If you bought the roving kit, then the above is all moot and perhaps you either aren't setting it up quite right, have a faulty bag or, without wanting to cause any offence, have a...shall we say "different" body shape and size that doesn't lend itself to such a combination.