Xpantastic!

On my Xpander, each pair of oscillators are always a bit out of tune with each other.  The amount of detuning is different on each voice, but consistent per voice, being off by +/-3 cents.  The tuning procedure doesn't resolve the issue. Nor do hours of warmup time.

Of course, it does create a nice analog slop to patches, but it just doesn't seem right.

Any ideas on a cause, or solution?