ya that sounds like there is a short someplace. The PCBs look really high quality though, so I doubt if it's a fabrication error. Maybe there is a horsey solder bead somewhere?
The maple basically just sends serial data to the driver built into the LCD, so it it gets garbled during transmission due to a short or bad connection, the LCD has no way of realizing it has munged data and displays it anyways. That's why you get odd characters.
Also I noticed that the kit LCD is backlit. Will it work with a non-backlit one as well?