Wondering if anyone else has come across this and what the resolution was -

I have an m15x which I just adore, but the w key seems to have a bit of an issue. It's used in most games to move characters forward, but it stalls out after a couple of seconds. For example, I will press and hole the key to move forward, and my character will start moving, but will stop in a couple seconds. I have to let go of the key and press it again which repeats the cycle. I constantly have to activate auto-run as a workaround, even over short distances.

Am I looking at a keyboard replacement, or could it be some other issue?

Thanks