While 5.4 used to work fine, and 5.5 Preview 1. Now with the latest code from the 5.5 branch, I also get those errors. It seems somehow UBT enables the Intel SPMD compiler and that’s why it fails:
#if INTEL_ISPC
include “NiagaraDataInterfaceVectorField.ispc.generated.h”
#endif
0>GeometryCollectionComponent.cpp(94,10): Error : ‘GeometryCollectionComponent.ispc.generated.h’ file not found
0> 94 | include “GeometryCollectionComponent.ispc.generated.h”
0> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0>1 error generated.