Thanks for checking this out Eric. You guys are awesome. I wanted to let you know that after doing some testing and re-targeting against the source (4.7.6) and then re-targeting back for some testing, it happened to resolve itself w/out any changes. I didn’t see it fail for any of my other hard coded references for any other asset but maybe if I had did a Clean/Re-Build then it would’ve fixed it. Maybe some file in Intermediate that never thought it needed to re-build itself maybe.
But glad it worked 
but I unfortunately can’t test any methods to resolve this out but I’ll let you know if it becomes an issue again. Most of these references are going to be overridden from BPs but some of the base classes need a base asset to default to.
Oh and as a heads up if this helps… I would reference the assets like so…
struct FConstructorStatics
{
ConstructorHelpers::FObjectFinderOptional<UMaterialInstance> MI;
FConstructorStatics() : MI(TEXT("MaterialInstanceConstant'/Game/Core/Materials/MI_Shard.MI_Shard'")
};
static FConstructorStatics ConstructorStatics;
if (UGameExtensions::IsValid(UMaterialInstance* MI_Asset = ConstructorStatics.MI.Get()))
{
// Do Something...
}