Automatically going left

[Taevas]

I massed on a server the following :

I don't know if it's my keyboard but there's something wrong. By vigouriously
pressing the arrows keys sometimes my graal character goes to the left
direction. I tried reconnecting, restarting graal, unplugging/plugging keyboard,
nada. The only way to stop this is restarting the computer. Though it (my graal
character) stop going to the left when writing or holding CTRL or ALT.

I received this helpful PM :

press Num Lock and start pressing buttons on the number pad

keep trying it, it should fix it

It happens to all Graal servers (playerworlds, didn't try Gold servers)

I want to know why this happens and how to make it not happen.

Thanks.