A battery-powered Thread leak sensor "supports mute via automation" and "goes quiet when you press the button" are two completely different claims. Only one of them is on the product page, and the gap between them is not a bug — it's how sleepy devices work.
Why the command waits
A battery Thread node is a sleepy end device. To conserve power it turns its radio off and only wakes for a state change or on its own polling interval. Any command you send — mute included — sits in the parent router's buffer until the sensor next wakes up and asks for it.
In practice that's tens of seconds for most devices and minutes for some. Nothing is broken. The protocol is working exactly as designed, and the design trades latency for battery life because that is the trade a battery sensor is supposed to make.
This matters far more when the sensor is somewhere annoying to reach. If it's up a ladder or behind a roof hatch, basic arithmetic says somebody is climbing either way — so make the trip count. A siren that keeps screaming for three minutes after you hit mute has thrown away the entire point of remote control.
Split the detector from the noisemaker
This is the fix with the best reliability story, and it isn't close.
Put a plain leak probe where the water would actually appear, and put the siren somewhere you can reach. Now the audible device is mains-powered, always awake, and instantly controllable. The unreachable part only has to successfully send one message when it gets wet.
That single-hop reliability story is much stronger, and there's a second benefit people don't expect: muting no longer silences your other channels. Push notifications, dashboard badges, whatever else you've wired up keep alerting at full volume even after the speaker has been told to stop. With an integrated siren, "mute" tends to swallow the whole alert.
If the siren has to be built in
Check before buying whether the device exposes the buzzer as its own endpoint or switch entity. Recent firmware revisions for some models have started doing this, which is why you'll suddenly see people having an easy time with a device that used to be stubborn.
That's a vendor-specific choice, though. There is nothing in the Matter water-leak device type that obliges a manufacturer to expose an onboard buzzer as a controllable switch. Two sensors that look identical on a spec sheet can behave completely differently, and you generally can't tell which from the listing.
Re-arm behind the mute
Whatever you end up with, don't let mute mean silent forever. Put a re-arm condition behind it: muting acknowledges the current alert, and if the probe still reads wet after some interval it should start again.
Without that, the first false alarm permanently disarms the one sensor protecting the space you cared about. It's a small automation and it's the difference between a muted sensor and a disabled one.
Point probes vs rope, for roof windows specifically
Point-type probes only detect water that reaches the exact spot where the contacts are. They also generate a steady stream of false alarms from condensation running down a cold frame — which is precisely the environment a roof window provides.
A length of leak-detection rope run around the whole frame catches far more real leaks and ignores far more harmless ones. Pair it with a humidity reading if you can, because for a roof window the useful signal is a humidity trend that stops behaving like ordinary nightly condensation. An instantaneous value rarely tells you anything; the trend does.
If you're specifying this rather than buying one
For a single sensor this is a shopping decision. Specified across a building, sensor-related callbacks are the expensive part of the job, and the questions worth asking a supplier change accordingly: what the wake interval actually is, whether the buzzer is an exposed endpoint, and whether a mains-powered siren variant exists in the same family. Those are covered in the smart home sensor ODM guide, and the battery-sensor hardware behind them is documented on the door and window sensor manufacturing side.
I work on the manufacturing side of this hardware, so I'm biased toward splitting the siren out to something reachable and mains-powered rather than trusting a sleepy battery node to take a command in time.
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