It's a Vive controller design issue, hardware-related. I've noticed it happening in other games too.

There's no code in the game that could cause this. :/

The bug has been around for a long time and I second the fact it's a hardware/steamVR issue. I made a walthrough of 'How to Ice' months ago and I remember it being in the video. I didn't talk about it, just clicked my grips to clear it. I only bring it up as a marker of how long it's been around.

Damn, for some reason it happens much more frequently now...