Hi Paul,
In both masters PinY was not recalculated.
Where a value of Height(6mm)/2 should have shown 3mm, there was 12,..
Editing the field without actually modifying it, got the right value back and corrected the position of the subshape.
This modification was possible in both the drawing and the stencil.
But the stencil made Visio crash every time I tried to save it.
So I created a new stencil and saved it. cf attachment.
I speculate that you used some code to generate the masters and did not properly update them
HTH some how,
Y.
PS: Saved the VSX as VSS and then back to VSX. Could not reproduce any failures.