Digi Deck makes graphics uglier

HI folks -

Editing SD NTSC 8bit in FCS2 with Aja Kona LHe connected via SDI to a Sony
DVW-A500 Digibeta Deck. This deck is fed reference via an AJA Gen10 Sync generator.

When I do an A/B comparison of the the deck output vs direct from the LHe card
there is a significant difference.

This material is a heavily graphics-effected:
The deck seems to introduce all kinds of additional crazy buzzing, pulsing & undulating.
When I A/B bars & tone they look the same to my eyes (no external scopes though).

None of this is a shock:
these graphics have all sorts of tiny criss-crossing lines and un-video friendly colors,
what is surprising is the difference that adding the deck into the signal chain introduces.

I am wondering if there are some deck settings, AJA control Panel settings or additional gear (TBC?) that could help with a cleaner output.

Thanks
- Jesse Gordon