I've been doing some more digging and ran across this post:
THis is the same problem I am having. Another problem this post addresses is that you cannot snap to a PG geometry node using OSNAPS was the tutorial states. My workaround was to draw construction lines and snap my geometry points to these entities.
Is this a know bug in part builder?
Is there anyone at AutoDesk that can confirm that complex structures built in part builder such as the drop manhole in the tutorial cannot accurately be shown as a boundary?