After more fooling around with deleting builds, deleting the copy from the App Store, and so forth, the problem no longer reproduces. So, that's good, I guess, but I'm not in the position of being able to file a useful bug report.
But to answer your questions:
The helper is an app bundle with LSBackgroundOnly set true in its Info.plist.
I launch it using NSWorkspace.
I granted permission to the helper, not the main app.
Since the helper is background only, not a LSUIElement, I'm not sure that what you're saying there is relevant.
Topic:
App & System Services
SubTopic:
General
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