Home app — HomeKit — always updating batch of devices

Every time I open Home App — on my iPhone, Mac or iPad — all devices will show their status for a second but then a batch will switch to updating for at least 10 seconds. Batches of devices seems random. All my devices software are updated. I have over 25 Homekit devices from various manufacturers: a mix of Eve, Lutron and other but all of them would suffer the same issue. My HomeKit hub is the latest Apple TV 4K (MN893VC/A). Thank you for your help.