In the host family there is a nested generic model family.
The nested family has several type parameters for Width, Height & Depth.
The host family has the same parameters for Width, Height & Depth and they are associated to the nested family parameters.
Everything works as expected until you decide to set the nested family Shared and load it back into the host family.
When loading back in you receive the following error message:
While reloading family 'Family Name': type(s) of a shared family cannot have their properties driven by parameters of the host family – fixing.
When you click OK to fix, Revit removes the associated parameters and sets them to standard type parameters.
Revit does this because the nested type parameters cannot be shared in the host family. Instead edit the nested family, and change the parameters from type to instance.
Once the parameters are set to instance, the family can be set shared and loaded back into the host family. With instance parameters any associations will be maintained in the host family.