Creating an instance of FLegacySlateFontInfoCache fails

Hi,
I was wondering why this simple code fails…
FLegacySlateFontInfoCache p = FLegacySlateFontInfoCache::Get();
Just wandering through the code and found out that it crashes somehow but i can’t explain why…
It seems like as if it requires somehing else should have happened before calling it. Thanks
Version 4.6