And you're using just a duo node? I'm perplexed since my install sounds similar to yours and it's working fine.
Yes, duo node with a tap in the feed to one Hopper for the HIC. HIC hard wired to the router. Everything else is RG6.
The problem is now more describable. If a network reset is done on either Hopper the other Hopper is visible for about a minute. The other Hoppers drive can be seen fully for about 30 secs, then only the PTAT, Rentals and Deleted Items folders will show, then the other Hopper disappears. After that the MOCA network shows only the Hopper and linked Joeys for that Hopper, but the HIC shows in both of the Hoppers MOCA network. Internet connectivity is good, On Demand works on all 4 boxes.
On the bright side I haven't dropped any local channels from favs lists in the last day.