I have this assembly with several sub-assemblies that all update number, size, and position of different parts based on the overall size of the main assembly.  For this particular sub, it's essentially a box with different panels that cover different sections.  As the box grows/shrinks, the green corner panels move to stay at those corners.  The purple panels are our standard size panels, these fill as much of the gap between the corners as they can.  The grey panels are custom cut to fill the leftover gaps.  The purple panels in the center are to calculate the material needed to make the grey panels out of standard panels (4 20" panels can be cut from a single 120" panel, but 2 80" and 2 50" would require 3 standard panels); this is for the BOM, and they are normally hidden, while the grey panels are excluded from the BOM.  I can stop here and everything is golden; or as the kids today would say, we're gucci.  This sub-assembly updates flawlessly.  It only has one condition that is not quite like the real product.  Say the box shrinks in the L direction, to the point that the grey panel is to small; it looks odd and becomes more difficult to produce.  In that case, we remove one of the purple panels and make 2 custom grey panels to fill the gap; such as we have shown in the W direction.

Then I had a 1 am epiphany two nights ago...those are always the best.  I now have this assembly updating mostly as desired with that one condition fixed.  However, if the grey panels transition from 1 panel to 2 panels, or reverse, I have to either edit that sub and rebuild there, or edit the pattern (which fixes itself as soon as I start the edit).  I never have to actually change anything, its just a matter of forcing it to update correctly.  I have tried setting it rigid and flexible, everything is set to resolved, it's not in large assembly mode.  What else could I be missing that would allow the sub to update correctly without extra steps?

One thing to note, these grey parts are what I call fake parts.  They are for visuals only.  I made them with their base planes mated to the sub's base planes; the features follow the sub assembly sketch which locates everything in the assembly.  If the part moves based on the sketch, and then also changes size based on the sketch....things get really weird.