Errors compiling UE 5.5, MovieSceneMaybeAtomic.h

Simply a fresh Unreal engine 5.5 install and I am attempting to compile a project.
There seems to be errors in movieSceneMaybeAtomic.h which is an unreal engine 5.5 file:
C:\Program Files\Epic Games\UE_5.5\Engine\Source\Runtime\MovieScene\Public\EntitySystem

int32 Add(EEntityThreadingModel ThreadingModel, const int32 Value)
{
	if (EEntityThreadingModel::NoThreading == ThreadingModel)
	{
		const int32 Old = Payload;
		Payload += Value;
		return Old;
	}
	else
	{
		return FPlatformAtomics::InterlockedAdd(&Payload, Value);
	}
}

the code doesn’t seem to be errored, and I can clearly see a function definition in WindowsPlatformAtomics.h