I mean it’s a commercial product - if stability issues were a common thing, that would be well known and published.

It’s a mesh VPN so it generally has the same stability challenges as any other: Hamachi, Nord, Meshnet, Wireguard (which is the underlying protocol that Tailscale uses).

If the Tailscale client is running on the NAS itself, I’d consider that the first thing to troubleshoot.

NAS’s generally don’t have much extra processing power, and in my experience apps designed to run on them aren’t the most robust.

I have an ancient NAS on my network that could probably run the TS client, Injyst don’t bother. TD runs on all desktops and servers (for general access), but connectivity to non-TS devices goes through the server running as a TS router. That can be run on any device running TS - it’s just a feature to enable and configure.