Apple Home stops showing ElectricalPowerMeasurement (per-tile watts) on 3.10.3 — 3.10.2 is fine

[RizJav]

Summary

After upgrading from 3.10.2 to 3.10.3, Apple Home no longer displays the live
wattage on bridged devices that expose ElectricalPowerMeasurement. The tiles
render as plain On / Off, with no reading on the tile or in the accessory
detail view, and the room's aggregated Power summary disappears.

Pinning the image back to luligu/matterbridge:3.10.2 restores it immediately —
same plugin, same config, same Matter storage, no re-commissioning. Moving
forward to 3.10.3 breaks it again. I've flipped the tag both ways to confirm.

The devices themselves are unaffected: On/Off still works from Home, and
Matterbridge logs ElectricalPowerMeasurement.activePower updating on every poll.
It is only the controller-side rendering of the measurement that stops.

Environment

Matterbridge	3.10.3 (broken) vs 3.10.2 (works)
Image	luligu/matterbridge:<tag>, --docker -childbridge
matter.js	0.17.6 (3.10.2) / 0.17.7 (3.10.3)
Node	v24.18.0 (in container)
Host	Raspberry Pi, Linux 6.1.21-v8+ aarch64, network_mode: host
Controller	Apple Home, iOS 27, single fabric, Apple TV / HomePod hub
Device	onOffPlugInUnit + electricalSensor on one endpoint, with PowerTopology, ElectricalPowerMeasurement, ElectricalEnergyMeasurement

The affected devices come from an unpublished local plugin (a power meter — it polls
a vendor cloud API and republishes the readings), but they're built with nothing but
the standard helpers, so this should reproduce with any bridged device exposing an
electrical sensor:

new MatterbridgeEndpoint([onOffPlugInUnit, electricalSensor], { id })
  .createDefaultIdentifyClusterServer()
  .createDefaultBasicInformationClusterServer(name, serial, 0xfff1, 'Acme', 0x8000, model)
  .createDefaultOnOffClusterServer(true)
  .createDefaultPowerTopologyClusterServer()
  .createDefaultElectricalPowerMeasurementClusterServer(null, null, 0)
  .createDefaultElectricalEnergyMeasurementClusterServer(0, 0)
  .addRequiredClusterServers();

Updated on each poll with
updateAttribute('ElectricalPowerMeasurement', 'activePower', milliwatts, log).

Steps to reproduce

1. Run Matterbridge 3.10.2 in childbridge mode with a plugin exposing the endpoint
   above; commission the childbridge into Apple Home. Tiles show On • <n> W.
2. Change the image tag to 3.10.3 and recreate the container. No other change.
3. Apple Home tiles now show only On — no wattage on the tile or in the detail
   view, and the room Power summary is gone.
4. Change the tag back to 3.10.2 and recreate. The wattage returns within a couple
   of minutes, without re-pairing.

What I ruled out

I went looking in my own plugin first, and it isn't there:

• The attribute is written and the cluster is live on 3.10.3. The log shows
  Update endpoint <MyMeter>:2 attribute ElectricalPowerMeasurement.activePower from 629000 to 1054000. updateAttribute() logs an error and returns false when
  the cluster or attribute is absent, so a successful update proves the endpoint
  really does carry the cluster.
• Apple is still subscribed. On restart:
  Reestablish subscription » … isFabricFiltered: false maxInterval: 3m 6s.
• The endpoint advertises exactly the same thing on both versions. I built the
  endpoint above under 3.9.3, 3.10.2 and 3.10.3 inside a real ServerNode and
  diffed Descriptor.deviceTypeList, Descriptor.serverList, tagList, feature
  maps, attributeList, numberOfMeasurementTypes, powerMode, ranges and
  cluster revisions. Byte-identical across all three (EPM rev 3, EEM rev 2,
  PowerTopology rev 1).
• Not the endpoint count. Going from 9 bridged endpoints back to 8 changed
  nothing. (This was my first theory — a controller subscription-path budget — and
  it was wrong. Noting it so nobody re-runs the dead end.)
• Not BridgedDeviceBasicInformation rev 5 → 6. That landed in 3.10.0, but
  3.10.2 works.
• No endpoint renumbering — checkEndpointNumbers logs no warnings — and the
  plugin code is identical across the whole comparison.

Suspicion

The only 3.10.3 change I can see that touches Matter-visible structure is:

[matterbridge]: Add a wired AC PowerSource to server nodes.

That alters each childbridge's root node rather than its endpoints, which fits
the symptom shape: Apple still drives On/Off from the same endpoints but stops
reading the optional measurement clusters. My guess at a mechanism is that adding
PowerSource to the root node of an aggregator changes how Apple models the bridge
and invalidates part of its cached view — Apple resumes its existing subscription
rather than re-reading, so a stale model would persist.

Questions, in case they help:

• Is the server-node PowerSource added unconditionally, including in childbridge
  mode where the server node is an aggregator?
• Does the root node also need PowerTopology, or a deviceTypeList entry, for a
  controller to accept a PowerSource there?
• Given Apple's reaction, would it be worth putting it behind a flag?

Happy to test a patch or gather more logs — I can flip tags on this system freely
and have a reproducible before/after.

[Luligu]

Hi,
first of all thanks for the super clear analize.

Can you please show me where you see electrical measurements with 3.10.2 on Apple Home (a screenshot) ?

Can you load with matterbridge-test (enable them in the config) plugin so we have the same source code ?

I see nothing at all with Apple Home ... with any version. So we start from there :D

[Luligu]

Any news ?
I'm curious...

[RizJav]

@Luligu apologies I had my notifications turned off, will send them details later on today.

[Luligu]

The root endpoint's Power Source cluster is now gated behind a new --root-power-source CLI param and is not added by default anymore.

Could you install the matterbridge dev version and retry without the flag? That should restore the pre-3.10.3 behavior on the root/aggregator node. Let me know if the ElectricalPowerMeasurement wattage comes back on the Apple Home tiles.

[Luligu]

One more thing to check while you're testing: please verify that the electrical measurement attributes (activePower, energy values, etc.) are never null on your endpoint — they should report at least 0 instead. null is spec-compliant for these attributes (it just means "value not available"), but Apple Home appears to gate/hide the reading on the tile whenever it sees null, even transiently. If your source ever reports an unknown/unavailable value as null before the first real reading arrives, that could independently explain a missing wattage display regardless of the root PowerSource change.