HDMI 2.1 Bug on 2020 AV Receivers Affects Xbox Series X but Not PS5... Why?

We test the Xbox Series X, Sony PS5 & RTX 30 Series cards with a Denon X2700H AV receiver to find out which ones successfully pass 4K@120Hz video signal using the HDMI 2.1 signalling method through the receiver to an LG CX OLED TV. webpage on 4K120A vs 4K120B vs 4K120AB: Japanese teardown of PS5, revealing HDMI 2.1 chipset from Panasonic Semiconductor Solutions/ Nuvoton Technology (MN864739): Zeskit Ultra High Sp