Peter,
Try setting your Flashback delay to buffered mode, instead of true bypass. A buffered pedal driving the Quaverato tends to work better because of the input impedance and the internal filter circuits. Another thing you could try while the Quaverato is in the pedal chain is to adjust the HIGH and LOW trim pots to settings that sound more natural. But I think you’ll find that driving it with a buffered pedal will help.
Good luck.
-Brach