Suddenly No Audio Output

Scaler 3.2, I’ve got Scale Notes Mapped checked. Suddenly I only get sound out of Scaler with about every 5th or 10th keypress. The keys in Scaler highlight each time I press them. Just sporadic sound coming out. I spend about 30 minutes checking Ableton, Scaler, etc… Then finally open a new MIDI track and it works perfectly fine with the exact same settings.

Is there something I’m missing?

Thanks!