Hue dimmer/switch v2 and Hue smart button not working since 2026.1

I have a couple of Philips Hue Dimmer/Switch V2 that have been controlling lights in my kitchen for the past year. I also have a Hue Smart Button that has been controlling a table lamp for several years. They were managed by ZHA. and the automations were simple and worked well.

After the January update my HA installation started misbehaving - automations not working, lights not coming on etc., to the point that I had to create a complete new installation, re-integrating all my devices and re-writing the automations. A faff but but not too bad except for the Hue devices. I can connect them to ZHA and when I check the activity section I can see events being picked up when I press the buttons but even the simplest automation using a Hue button trigger fails to work. I’ve tried to track hue-events in the developer section but that yields nothing. I do get responses if I track zha-events but I cannot make sense of the data that is returned when I press a button.

I’m at a bit of a loss now and I wondered if there has been anything in the latest updates to ‘break’ the Hue devices. I’ve not found anything from Google searches on the subject.

Anyone else come across this issue?
Thanks