ZigBee bulbs disconnected in ST app but work fine in Google Home

I have two Zigbee Osram bulbs, ST will often say they are disconnected but Google Home will be able to operate them fine. As they are connected to Google Home through ST this really confuses me. Any ideas?

I’m having a kind of similar issue.

Z-wave switch that shows disconnected in app but works perfectly via Alexa.

My, very uneducated, guess is that Alexa and Google Home blindly issue commands. And that the problem device is (obviously) receiving but can’t send updates or status.