It impacts the c7 too. It has improved a lot, but is still very intermittent. In fact it happened to me this morning for the first time in weeks.
What is everyone doing to recover from this? Restore from backup including z-wave restore or shutting down fully and pulling the power cord for a minute or two or something else? Last time I did the restore which worked for me. The time before when I didn't know what was causing the problem everything got in a right old state and I ended up trashing my z-wave entirely and starting from scratch as I only have a handful of z-wave devices.
This has moved off-topic. Questions about backups, Z-Wave, etc. all have other homes and answers elsewhere.
This topic has run its course.