I have a VK202-24 USB display. Whenever I use a custom font or create my own font, if the pixel at the bottom (left or right, I don't remember right now) is lit, I get a bright underline for that character. it really is quite annoying, especially with animated displays. I have lived with this because I thought it was unavoidable, but I recently saw a video clip of the same display and it did not manifest this behavior.
Welcome to the forums, the reason the underline turns on is because the 2x20 VFD is a 5x7 font not a 5x8 font like a LCD would be. What you will have to do is stop using the bottom custom characters row, and that twill stop the line from showing.
