Bug: qfc-item-controller-cleanup-timer-and-stale-field-defects

[drmoisan]

• Work Mode: minor-audit

Summary

QfcItemController.Cleanup() nulls the armed _emailIsReadTimer field without disposing it,
orphaning a live 4-second System.Threading.Timer that will still fire against a torn-down
controller. The same method leaves other collaborator fields in an inconsistent state.

Environment

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Steps to Reproduce

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Expected Behavior

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Actual Behavior

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Logs / Screenshots

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Impact / Severity

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Source

From: docs/features/potential/2026-08-07-qfc-item-controller-cleanup-timer-and-stale-field-defects.md