@JED2021 : I feel your question has not been answered.
That bullet point in the release notes is pretty meaningless. What sort of "device stability issues"? How frequent might the issues manifest? How much does it increase the instability? (from zero events to one every day? Or from zero events to one every year? Doesn't say...).
All the other bullet points in the release notes are useful, except that one.
I've opened a ticket with Meraki asking them these same questions, and they have yet to provide a real answer.
I've asked a similar question about release candidate versions on a different forum post, and a Meraki tech basically said "it is up to you to decide whether it makes sense to install."
But how is anyone supposed to make an informed decision when we see this warning without knowing the level of risk involved?
At this point, despite the fact that the RC version could solve a major client VPN problem, I'm going to have to hold off and find a different (non-Meraki) solution.