The shared parent-pair child loop read group.childIds[i] while iterating
the filtered childCenters, so a child without a position would desync the
id from the centre — and that index now also drives the active-connector
lookup. Ride the id on the mapped {id,x,y} centre so the two never drift;
a positionless child drops out of both together.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>