Had this issue on a c-7 as well, upgraded to a c-8 for the better antennas (and already see the advantages after a couple of hours), but getting zwaveCrashed every hour or so (Not exact, but on the c-7 it was often at :00 or :30 minutes after the hour).
When it happens, all the devices physically work but for 5-10 minutes the hub won't send or receive any messages from the z-wave network (so no automations work), and then it'll report zwaveCrashed, recover, then everything continues working.
Mostly just an annoyance, but a 5-10 minute outage for automations every hour or two (16 events yesterday on the c-7, 3 events so far today on the c-8 installed 3 hours ago) is having a pretty significant impact on WAF.
Submitted a support ticket too, but no place to put real information there, so I figured I'd start a topic here for public visibility and a better way to communicate as well