I have an assembly of a mitre hinge that I downloaded from a supplier's website as a STP file. I saved it as an assembly, with all the individual parts fully constrained. I made a design table with the angle of the hinge as the only variable.
Now, every time I save the main assembly, in which I have used a number of these configurable hinges, the configurable hinge is also saved, even though I have not changed it.
There are a couple of other configurable parts and assemblies in the main assembly, and these are not saved every time.
What is the most likely cause of Solidworks thinking the configurable assembly has changed when it has not (at least, not intentionally)? What am I likely to have done wrong (this time...).