Blackwidow Chroma M1-5 Keys stick

Hello,

I have a problem with my M1-5 keys on the Blackwidow. I've had them keybound to 6-0 since I got the keyboard years ago, but since the new Synapse launched, they have been sticking. So hitting M1 once (which is bound to 6) outputs 66666666.

This is a problem since tapping the button to activate an ability in WoW means it lags significantly before the ability goes off.

I've rebound it, made sure Turbo mode is OFF, reinstalled Synapse. Is there a bug or something I'm missing?