On macOS, when using Tailscale’s DNS settings, unqualified node hostnames do not resolve. They do resolve inside the tailnet domain; e.g., tailxxx.ts.net.
This only occurs on macOS; my Linux box can resolve unqualified hostnames just fine.
Also, nslookup resolves them just fine. But I’m given to understand that macOS applications use a different resolution strategy from nslookup.
Weirdly, even though I have global DNS override turned on, scutil --dns shows that I’m still using my local DNS resolver (in addition to 100.100.100.100). But this shouldn’t be a problem, because my local network uses the same DNS server as my tailnet, and clients on this network have the same name as on the tailnet, so the same name should resolve to the same client no matter which network is being used.