I ran into the same issue, and I actually pinned the problem down to cl.exe itself.
There are different builds of cl.exe for different architectures, including a x86 build and a x64 build. You can find out what arch your cl.exe is using by doing "where cl.exe". I had a x86 build of cl.exe.
I switched to the x64 Native Tools Command Prompt for VS2019 and did a scons build from that prompt and the link errors went away, resulting in a successful build.