No, there would be no need to power cycle everything at the same time.
Generally for this error these are the main things I would look for:
- Z-wave network signaling/routing is bad for that device. Your responses suggest this shouldn’t be an issue, but I cannot verify the actual connection data with any diagnostics for non-Surety users unfortunately. It would be good to have your current provider look at dealer tools to make sure that your Tstat shows neighbor nodes and good signal quality.
- Incompatibility, but your responses wouldn’t suggest an issue there either. Just to make sure though, are you running any other Z-wave controllers? Is the GC2 a secondary controller in the network?
- Software error. I would try updating firmware if possible, though this is a long shot and your current firmware should work fine.