I get this same noise pattern on a Rx board I built, but it's on the receiver side (happens on a number of chargers). Does it have to do with the resonant capacitors not being the proper values? It's not as audible as that (I would have to put my ear directly next to the Rx board to hear that) but it is obvious from the LED indicator in that it pulses with the pattern. Further, when probing one of the coil inputs to ground, it is noticeable on a scope.
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