The power issue sounded interesting...
I've been using a 12V 2.5A supply, which is the largest barrel jack 12V supply I have and above the 2A spec that the HC2 product info recommends. I did try to remove the 3.5" drive before booting up the configured omv system to reduce the power load on startup but it still behaves the same.
The other thing that makes me suspect it isn't a power issue is that when I do a fresh install of omv (with 3.5" drive installed) it boots up and connects to the network quickly/reliably every time.
At this point I think I'm going to switch over to an R Pi system since the HC2 just doesn't seem to cooperate for me.
Well, maybe I spoke too soon! I tried it one more time with the drive removed and now it boots and connects to the network. So looks like the power supply could indeed be the issue. I'll get a better one ordered up and see how it does. Thanks guys!