Why is auxiliary heat running during cooling mode on my heat pump system?

For heat pump systems, this is typically caused by a wire being incorrectly attached to the W terminal on the UWP. Verify there is no wire connected to the W terminal, as the W terminal should not be used for heat pump applications. (Page 13)

From the official Honeywell Home T6 Pro Th6320u2008 manual, page 13

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