$50 Reward ~ Materials Missing When I Play the Level

I’ve imported my Character in UE, assigned the materials, and made sure the connectivity between the two is set up properly. However, when I play the level the materials for the upper body, face, and eyes go missing. Is there something I’m missing that causes this error? When I stop the level, the materials return to normal.

The answer that solves the problem gets $50 sent to their Paypal!