Sounds like a bug to me, if you are actually using two sawtooth waves? 
Maybe a simple sine LFO on the pitch of one OSC would lead to similar results? Synth1 on macos is totally buggy.
Sounds like a bug to me, if you are actually using two sawtooth waves? Maybe a simple sine LFO on the pitch of one OSC would lead to similar results? Synth1 on macos is totally buggy.