I never had any policies in learning mode, but just in case, I tried turning off Policy Learning in System Features. It looked very promising, as I didn't experience high reportd CPU usage for several days. Unfortunately, the problem occurred once again just now.
As I said previously, there was a spike immediately after upgrading to 5.4.4 that led me to think it didn't resolve the issue, but CPU Utilization has been as expected in the two weeks since that particular spike.
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