In my case, I did have to remove the modulename macro as @MaselinoM mentioned, but I also had to adjust my build.cs to directly reference the module that owned the enum.
So even though I had PublicDependencyModuleNames that meant modules A, B, and C had this relationship:
A depends on B depends on C
where C had the enum and I was using it in A, I still had to reference C directly from A in A’s build.cs to get it to link. Pretty sure that isn’t the way it should work with the public dependency list, so any insight here would be helpful.