Looking at the relevance at bit more and I think the issue is the registry key hives have been reversed.
If you look at the the 2 fixlets for KB5021045, fixlet 502104503 for 32-bit SQL is looking at x32 registry and fixlet 502104503 for 64-bit SQL is looking at x64 registry.
Now compare that with the 2 fixlets for KB5021037, fixlet 502103703 for 32-bit SQL is looking in the x64 registry and fixlet 502103701 for 64-bit SQL is looking in the x32 registry.