I'm using the belt/chain feature for a conveyor belt, and have created a belt model around the derived sketch that it creates from the auto-generated sketch belt profile.

Now, I've changed the size of the rollers that the belt runs around. The generated sketch updates correctly, but the derived sketch within the belt part doesn't change. It remains fixed to the profile that it was before the roller size changed.

The outer sketch profile is the auto-generated sketch which has correctly updated to the new larger roller.

The inner sketch is the sketch derived from the above, which should have udpated to match it:

The derived sketch has a question mark against it:

I thought this meant that a reference couldn't be found, ie. it has lost its link to the original Sketch2, but if I view its external references it is 'in context':

Am I doing something wrong?

Thanks,

Tom