Hello so i have a Redragon karura K502 Keyboard and the keyboard is great , its silent and has rgb and all that stuff , however when i play games like arma 2, the issues start to come in, for example if i hold w + d to move around in different directions, my character looks like he is twitching around, but as soon as i hold 1 of key it works perfectly fine ? If someone knows the fix please help me, it has the "Fn" function key as well so idk if that would help but there you go ! 
Any help would be appreciated
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Link to keyboard : https://www.amazon.co.uk/Redragon-Karura-Keyboard-Notbook-Computer/dp/B00LSGKEC4

Any help would be appreciated

Link to keyboard : https://www.amazon.co.uk/Redragon-Karura-Keyboard-Notbook-Computer/dp/B00LSGKEC4