Not odd at all. The noise source is in a side lobe in one case and in a null in the other. Antenna pattern changes all
over the place as you move away from the optimum frequency of a yagi. Happens all the time. I once found a condition
where my HF tribander pulled in a 2 meter signal better than a 10 element 2 meter yagi mounted several feet higher.

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Crazy George
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