Character Stops Walking Every Few Seconds

[JustAPileOfBeans]

Hey all! Hoping someone has a fix for this. My friend and I are trying to play together, but he's running into an issue where when holding down "W" to walk (also happens when using the mouse command) his character will just stop moving after a few seconds and won't move again unless he re-presses the key. We've confirmed it's not a hardware issue, and can't find anything in the game settings that could be causing it, so hoping someone here has a suggestion. Thanks!