https://bugzilla.kernel.org/show_bug.cgi?id=209713
--- Comment #14 from Michel Dänzer (michel@daenzer.net) --- (In reply to Frank Kruger from comment #12)
I am seeing the aforementioned warning at boot for kernel >= 5.10.10, with kernel-firmware-amdgpu-20210119 (AMD Ryzen 7 PRO 4750U). Kernel 5.10.9 does not have it.
This was originally reported for older kernels, and per comment 2, I was hitting it with the DRM code merged for 5.10 before 5.10-rc1. You probably just didn't hit it with 5.10.9 by luck.