I have just tried using Helix floor with it's AES OUT and SPDIF IN. I get the dropout/loss of clock. I've tried connecting it 3 different ways:
1) HELIX as the master digital device into a word clock generator, then word clock from the WC generator to all other gear (except HELIX).
2) Word clock generator as the master digital device, word clock or SPDIF to the Helix
3) HELIX AES into MOTU 112D (audio interface), wordclock from WC generator to all devices, including Helix SPDIF IN using a BNC to phono adapter.
The result is always the same, and I am running v2.12 on Helix. I have already suggested this problem be fixed, and include the ability to switch the HELIX SPDIF IN to act as a wordclock in.