ADC causing phasing on record stems

[Brandonx1]

Hi All,
I have a hugh problem with ADC. I have DX tracks that feed a St. aux with limiters on it then, the aux, feeds a stereo bus and a mono bus for deliverables. The stereo bus is fine but the mono bus is phasy. If I turn ADC off, the phase problem goes away. The only think I'm doing to the mono buss is lowering it 6 dB. I just had to re-record 12 shows of DX. Nice waste of a weekend. Also, this only happens with the interview tracks. The production DX has it's own paths and record channels but the same exact config and does not phase with or without ADC. Anyone else?
Best,
Brandon
Forgot to say PT 8 cs3 at the mix stage and PT 7.4 on the layback, stem recorder stage. Same problem with both rigs.