Live 8.2.7, OSX 10.6.8 on MBP 2.4G Core 2 Duo.

I'm having WC issues with 2 different I/Os. First an RME FF800 wich was swapped out for a MotU 828mk3.
WC is sourced off an AArdsync that is locked to house video.
The Aardsync is delivering WC to 4 other devices that are having no issues.
2 x48s, a Mackie d8b and something else I can't remember.

Symptom, I/O WC takes a hit and the dig out stops playing, as to be expected.
Go back to internal sync and all is well.
Swapped out drives (ext Glyphs).
Changed coax and WC sources, no change.
But I need to lock to WC as I'm providing ADAT outs to the Mackie.
The problem is very intermittent.

I have yet to see the 48K light go out on the 828 (which I'm on now), but I did see the WC take a hit on the RME.

I'd update to the latest Live if I was sure that would cure the issue, but I'm mid a long term show with only a week left to go.
Is it possible the FW connection has some relation in passing sync, so that perhaps the issue is the MBP?

OBTW, there are 2 systems synced with Cat5 and audiomidi sync to fire both as main and back up with a LaunchPad.
Both are MBPs of the same vintage.
The Back-up isn't WC synced as it is only delivering analog out of it's aggregate, Traveler mk3 and 2882.

Is perhaps, the window of opportunity, for the RME and 828 and others of this ilk, less forgiving for WC then more "pro" devices?

Ideas?