[Elecraft] KX3 - sounds like filter blow-by - what am I hearing?

I have been using a KX3 during FD, connected to some large (tower/yagi) antennas. Am operating CW exclusively. Although I've had the KX3 for a while, I've only used it casually until today's FD. All day I've been noticing (on 20 and 40M, with fairly strong signals - some ove S9 - across both

Re: [Elecraft] KX3 - sounds like filter blow-by - what am I hearing?

Another data point while testing - If the BW is set to an even bandwidth (say 100, 200, 300, 400, 500 Hz) the blow-by effect is very pronounced If the BW is set to an odd bandwidth (say 150, 250, 350, 450, 550 Hz) the blow-by effect is minimal or absent (not sure, but it is very minor.) The