Could you post the code where you’re setting it on construct? Also, are you setting it before the pawn even exists yet? Remember that there is an order of code execution, and if you’re creating the widget before the pawn is even in existence, you could be setting Char Ref to a nullptr.
Another portion to check would be where you attempted to use a cast instead of a variable reference. Is that cast failing, or succeeding? I would add a print string after the cast failed to double check.