Detuned phasing ?
 

I've had this issue with other presets from different VSTs as well.

Basically, I get a sound I like from the virus and create a melody, or arp sequence. After I hit play by the 4th or 8th bar of the melody I get some detuning and the melody sounds off key for a second or two.

Anyone know how to get rid of this and what's causing this?

Can you show an audio sample?

Which oscillators are you using?

If you're using the Hypersaw, this is unavoidable due to the way the phases of each of the waveforms are programmed to be randomly triggered on each key press. Consequently sometimes they are in phase, others times not.

Using Unison instead is much more controlled but of course is more expensive in terms of polyphony.

I switched the OSC from Hypersaw to Classic and still having the issue.

You'll hear it at :07
https://soundcloud.com/fallward/dee-choon/s-eGcWM

I've read about it before, on the official forum. I believe you should just go ahead and contact support. They know about it ;)