Mech keyboard fires twice

So I bought one of these cheap chinese mech keyboard.
It used to work well but after a few weeks, one issue started.

When I press the right arrow key, it registers the ff:

EventType | code | name
KeyDown   | 0x7c | right_arrow
KeyDown   | 0x7d | down_arrow
KeyUp     | 0x7c | right_arrow
KeyUp     | 0x7d | down_arrow

That means if I press the right arrow key, the cursor moves 1 to the right and 1 down which is very annoying.
It registers the same events above when I press the down arrow key but the down arrow key is bearable.

I'm using this on a MacBook Mid-2012 i7 and checked the keyboard events using Karabiner-EventViewer. I will try this on Windows later today but I'm not sure if it makes any difference. It's still under warranty but the problem with these keyboards is that sometimes when you return it you'll have to wait forever to have it back. Is there anyone who came across this issue or know if it can be fixed?