New, never-paired Thread device tries to commission to non-existent NEST-PAN network instead of HA Thread network

Configuration Matter/Thread
1

Setup:

  • Home Assistant OS 2026.2.1 on bare metal (HP Slice)
  • Home Assistant Connect ZBT-2 as Thread Border Router
  • OpenThread Border Router addon 2.16.4
  • Matter Server 8.2.2
  • Thread network: ha-thread-073b (Channel 15)

The problem:

When trying to commission any Thread-based Matter device (IKEA MYGGSPRAY motion sensor), the Android companion app always tries to connect the device to my old Google NEST-PAN-7222 Thread network instead of my HA Thread network.

What makes this unusual:

  • All Google Thread Border Router devices (Nest Hub, Google TV Streamer) are physically unplugged
  • Google Home app has been uninstalled from all phones
  • All Thread-capable devices were removed from Google Home before uninstalling
  • The NEST-PAN network is NOT visible in HA Thread settings under “Other networks”
  • The thread.datasets storage file contains ONLY the ha-thread-073b dataset - no NEST-PAN entry anywhere
  • Tested with THREE different Android phones including one that has NEVER had Google Home installed and uses a completely different Google account - same result, always tries NEST-PAN-7222
  • Tested with a brand new, never-powered IKEA sensor (no battery ever inserted) - same behavior
  • Google Play Services cache cleared on multiple devices
  • ZBT-2, Matter Server, Thread integration, and OTBR addon all fully removed and reinstalled - same result
  • OTBR REST API (/node/dataset/active) only shows ha-thread-073b, no NEST-PAN

What the Matter Server log shows:

When commissioning via phone (Companion app), the session establishes successfully on the HA fabric but the device ends up on the NEST-PAN Thread network. When the NEST-PAN Border Router is physically unplugged, the device becomes unreachable.

When using the developer commissioning tool (manual code entry) in HA, it always fails with Discovery timed out / Commission with code failed.

The mystery:

The NEST-PAN-7222 network ID is specific to my former Google devices - it’s not a neighbor’s network. Yet somehow, every commissioning attempt on every phone targets this specific network, even though there is no physical Border Router active, no credentials stored in HA, and one test phone never had any connection to this network.

Has anyone seen this behavior before? How can a specific, defunct Thread network PAN ID persist across multiple phones, a full HA reinstall, and affect a never-powered device?

HA Community thread link for reference: Solved - How to change the preferred network on my android phone

2

Try to restart your all windows devices, an phones and HA, as Matter/thread are using mDNS, and DNS-sd , and clear all APP-caches on the phones

3

Usually the culprit is that the NEST-PAN thread network credentials are stored on the phone and once that happens, the only way to remove is to clear both the Google Play cache and storage. How NEST-PAN thread credentials would get stored on a phone that has not used the NEST-PAN before is beyond my knowledge-base, but likely it too stored the NEST-PAN Thred creds.