It appears that @Patriot_1776 may be correct about the curse of the split circles contributing to this.
This is the explanation I got back from R&D on why the intent chain is failing and the edge is not. In this case intent chain for the full circle is not more robust than using an edge of the same arc.
“Section of the first pattern feature uses Intent Chain as a reference.
When the first instance is regenerated, this intent chain forms a circle - fine. But this extrude modifies the edge that this intent chain is based on.
When the second pattern instance gets regenerated, the intent chain is an arc - still fine. But this extrude breaks this arc into two and now the intent chain contains three arcs.
The third instance sees three arcs in the intent chain and fails to regenerate as Sketcher doesn't support projections of intent chains with multiple components.
This is the expected behavior.
Users can easily modify the section so that it doesn't use intent chain reference but just uses an edge (which is used anyway, in that sense the intent chain is redundant in the original model).”
