I posted at Gearslutz as well but I think this is a serious bug that need to be investigated 
I have issues with percussive sounds. There will be a “hickup” on each note on. I have tried mainly on poly mode. Note-on osc reset is off.
If setting the Amp envelope to delay 25ms the attack is fine, see picture.
And here is an audio example.
First normal attack and then I have added 25ms delay to the Amp env and the attack is fine.
Edit: I could not attach a wav file. So here is a soundcloud link but you really need to DOWNLOAD the file to be able to hear it.
https://soundcloud.com/mrfirechild/moog-one-attack-hickup-01
It would be very helpful to know what version OS you are running.