52 MHz crosstalk

We are facing a strange issue. Either if we are using LoRa or FLRC modulation. If we send e.g. a 2400 MHz, we receive 50% of those at 2452 Mhz. Some other frequence differences, close to 52 Mhz subharmonices receive either, but with worse quality.
That behaviour is symetric. If we send at 2480 we can receive 50% at 2428.
As 52 MHz is the SX1280 clock, this clearly is something SX1280 internal. Anyone else, who had recognized that effect or any information ?

The effect happens on different HW designs, our own and a 3rd party commercial design.