Guitar Playback has 'Warble'

Hi guys,

I’m in the midst of recording a song on cubase 5. There seems to be a problem whenever I record an ‘A’ power chord. It sounds fine when I’m recording but whenever I play it back there’s this warble as though the note is being played under water. For some reason, its only with this chord. It’s audible via speakers/headphones/custom IEMs.

Can anyone help? There’s no modulation involved, purely overdrive. I’m using guitar rig 5 as a plugin, so there’s no micing up of amps etc. I’ve tried this with two different guitar tracks with two different amp simulators but to no avail. I’ve also tried re-recording but the result is the same.

I can’t find any solution on the net thus far.