Problem with flexible parameters in assembly

Hi,

I can't find out what am I doing wrong with my chain assembly model.

End links and main links are assembled with MDX assembly constraints and flexible dimensions.

At assembly level, all these dimensions are controlled by relations and parameters.

And these parameters are declared flexible in the chain assembly model.

Up to this point everything works fine : when I change parameters, everything regenerate as expected in the chain assembly model.

When I integrate this chain in another empty assembly, the first link of the chain does not regenerate correctly when I change the flexible parameters. All others will regenerate as expected.

I don't get why.

Any hint ?