I was going to post that I've had that trouble too, but sent a line of symbols to demonstrate, and they all got through fine. Here they are:
≈ ≠ � ≤ ≥ Δ ∞ > � ⅛ � ⅓ ⅜ � ⅝ ⅔ � ⅞ � � � � � √ ϕ Ω �
Maybe Luap expanded the character set recently.
Edit: They all looked correct in the "preview" window. Squared, cubed, and the degree symbol were among the ones that got converted to question marks. One quarter and one half didn't make it through either.