Lynx Aurora x2, AES, Burl B2, Artist mix & latency

I'm aware there's a few different players here and it's highly unlikely that it's a Lynx only thing, but perhaps some guidance can be had with the kind folk here.

Basically I'm trying to solve a latency issue. 

At our studio we have x2 Lynx Aurora 16's, one hooked up via AES to compromise a total of 32 i/o -interfaced with the thunderbolt card. We also have a Burl B2 2ch AD, which we use for printing our 2ch mixes back through. It has AES outputs and we connect this by pinching 2 of the XLR tails of the last AES cable that connects the last 8 AES inputs of the second Lynx (DB25 to XLR breakout cable). In ProTools this comes up as Input 31-32 for those playing at home. The Lynx's are clocked off the Burl B2.

There's two resulting issues by the same latency issue at play here that are cumbersome.

1) When returning/printing back into ProTools from the Burl B2, it's delayed by quite a large amount. On average anywhere between 100-400ms, but as far as I can tell it's a moving target that varies day to day, mix to mix, buffer setting to buffer setting etc.

2) Perhaps the most annoying is the impact it's having on our ability to write time accurate automation with our Avid Artist mix. A parallel example would be playing a midi keyboard or instrument with the buffer size set too high so the sound coming through the speakers is later than what's being actioned. 

I've noticed that if I bypass the Burl B2 and just return back into the Lynx the issue is improved/non-existent so there's obviously something happening between the Burl and the Lynx at the final stage.

Does anyone have any suggestions on improving this situation?

Thanks