Hey I'm so sorry to hear that, I've only used UE4 but looking online it seems to be a rigify compatibility issue, but it could also just be a general blender to game engine problem. If you haven't watched already this video may help.
No problem, its also been on the back of my list of things for my game. Right now focusing on programming stuff and i have a place holder model i got from sketchfab. When i get more gameplay implemented ill try the rigging stuff again.
