Problem with UNO with USB Host Shield for USB keyboard hacking

Hi all,
I am working on a hardware keyboard remapper project (QWERTY to COLEMAK layout) using Arduino UNO (R3) with USB Host Shield .
I have already successful remap the keys I want and display in the serial monitor. But after I flash the UNO into USB HID Keyboard, it keeps sending weird keystrokes on my screen.

P.S. sketch is attached

qwerty_remap.ino (4.75 KB)