New RAM only works when mixed with old RAM

To start off, my PC specs: CPU: Ryzen 5 7500f GPU: XFX SWFT 210 AMD RX 7600 8GB Motherboard: Maxsun B650M Challenger Wi-Fi RAM:

• Kit 1 (old): 2x16GB JUHOR 6000MHz CL 46
• Kit 2 (new): 2x16GB Corsair Pro 6400MHz CL38 (White)

As mentioned, my PC will only post with the new RAM kit (the corsair one) IF AND ONLY IF one of the RAM slots on my motherboard has one of my JUHOR RAM sticks also inserted.

Mother board info: BIOS is updated to latest version 4.9G, 03/15/2025

To lay out the test cases (my motherboard only has 2 total ram slots): Slot 1: JUHOR, Slot 2: Corsair - > works Slot 1: Corsair, Slot 2: JUHOR - > works Slot 1: JUHOR, Slot 2: JUHOR - > works Slot 1: Corsair, Slot 2: Corsair - > won't even POST

Things I tried changing in the BIOS to no avail in fixing:

• setting the EXPO profile to either RAM stick types preferred profile
• turning on/off EXPO
• over/underclocking my CPU
• turning on/off TPM