Scene -> PanelSet -> PanelA is added right away when the PanelSet is created -> PanelB is appended to the stack from a user action -> Attempt to add PanelC from a user action will always crash.
And it's just using the simple child interface to add them:
m.newPanel = createObject("roSGNode", "NewCustomPanel")
As a sanity check I've verified that m.global.panelSet is what I expect it to be, and it looks like a sane PanelSet.
Is there anything about my interpretation of Panels that is wrong? Seems like I should be able to continue to add to the Panel stack without any issues.