Trackpad on MacBook Pro is improperly double-clicking

On a MacBookPro1,1, the trackpad button seems to be "clicking" after a button release, improperly making nearly all gestures a "drag" action. This only seems to be happening since 16.04, but it renders the trackpad nearly unusable.

Attached is a xev.log file to show a few clicks. You can see after `Button Release` there's a phantom `Button Press` event, according to xev.

I've physically opened up the MacBookPro1,1 and cleaned out the underside of the trackpad with compressed air to make sure that dirt or dust isn't causing this.

It's possible that this is just a hardware failure nonetheless, but if there's something software-related, I'd love to get it fixed.