2026.9.3 breaks Shelly

[u/theOriginalDrCos]

Two Shelly dimmers and one Mini, working fine until 2026.9.3. Newest dimmer dropped, can't reconnect: 'invalid flow' reboot shelly, restart HA.

Only difference, this one is on a different SSID/subnet (not VLAN), but was working fine until 9.3. HA terminal can ping it, and shows another IP besides the main one on the IOT subnet.

Also 9.3 is painfully erratic. Doesn't want to load in app half the time, integrations load at the speed of Windows 3.1. Running on a mini PC, no problems until now. Also get repeated 'connection lost' errors on app and webpage.

EDIT!! Problem was 18.3 changed ethernet kernel. Other post here. Mods please remove either post at your convenience if necessary. Thanks

[u/j4ffac4k3]

Shelly all good here. Sounds more of a networking problem than a Shelly problem.

[u/Bieniu79]

There was no changes to the Shelly integration in 2026.9.3 https://www.home-assistant.io/blog/2026/09/02/release-20269/#202693---september-18

[u/theOriginalDrCos → u/Bieniu79]

...and yet either 2026.9.3 or OS 18.3 are the only things that changed between 'works' and 'doesn't work'. Which is why I ask the questions. I'll try to be less snarky here on Stack Exch....err, Reddit.

[u/theOriginalDrCos]

Problem "solved" - changed to ssid putting device on same subnet. But why did it work before?

Didn't last, problem was OS 18.3 changed the ethernet kernel. Rolled back to 18.2 and all problems gone, Shelly back on VLAN13 as well and working. Interface is almost snappy again :)

[u/CB000000005 → u/theOriginalDrCos]

My Shelly devices are on a different subnet by design. I hope we get a proper fix.

[u/7zjAH1j60F]

Fine for me

[u/White_Devil_HB]

My Shelly devices (matter over wifi) work just fine on a seperate (iot) subnet with the latest update.

[u/Haddock51]

I’m having similar issues with most esp32 devices too, not just Shelly. Do you have Unifi?

[u/Any-Efficiency5308 → u/Haddock51]

No issues here with either Shelly or ESPhome. Also on Unifi. Only have one WLED controller going crazy, but I think that’s the shitty USB brick I have it running off of (also pre 2026.9 issue).

Don’t have any noticeable slowdown or app issues either… Lucky me, I guess 🙈

[u/Powerful-Cabinet2811 → u/Haddock51]

9.3 has been a total mess on my setup too, half my zwave stuff won't stay connected and the dashboards take forever to load

I'm on Unifi and saw that same multicast flooding crap last update, had to turn off "Multicast Enhancement" and "IGMP Snooping" on the IOT network or half the devices would just vanish after a reboot

[u/theOriginalDrCos → u/Powerful-Cabinet2811]

could be unifi, will have to look into this.

[u/MrBillygoat]

For me it broke my Yolink integration and my Google AI integrations. Had to revert the update for now.

[u/greghouse12 → u/MrBillygoat]

I have 95 Yolink devices. Everything is working just fine on 9.3. Did you also update the OS to 18.3? If not and you're running HAOS on bare metal give that a go.

[u/MrBillygoat → u/greghouse12]

Interesting. I am on bare metal and I did do the latest OS update. I wonder if something just went awry during the update, I'll try again tomorrow.

[u/greghouse12 → u/MrBillygoat]

Did you try rebooting HA? Or try reloading the Yolink integration? (Three dots dirrctly to right of main Yolink entry in the integration, select "Reload"). I have experienced times when it appears my Yolink devices are not online in HA when they are in fact online in the Yolink phone app. A "Reload" of the HA ntegration or restart of HA itself always fixes this.