lemp9: Number Key row issues

[blakeridgway]

I have discovered a interesting issue with the Lemur Pro that involves the Number Key row.

When pressing a more than two keys in succession cancels out the press of the keys after the second key that was pressed.

i.e: When pressing 123 the only keys that appear are 12.
Attached is a .zip file of a video of what I am experiencing.
VID_20200422_082640.zip

[crawfxrd]

This is expected behavior. Certain key combinations do not produce output in order to prevent ghost keys (#24). So while '1' and '2' are held, pressing keys such as '3', '4', 'r', 't', will not produce any output. Such combinations can be determined by looking at keymap.h for a board.