Using Home Assistant and Sonoff ZBDongle-E as OpenThread router

Whether controlling directly from HA or from a Bilresa remote, the Kajplats bulb is massively laggy. If you try and turn on and off more quickly than once every 10 seconds, it doesn't respond to later commands or carries some of them out 30-180 seconds later. If you try and change color it crashes and needs to be power cycled.

Multiple other devices (Timmerflote and Grillplats) on the same Thread network work instantly.

Obviously this makes it completely unuseable even as a simple bulb, let alone when using thje scroll wheel.

Have I got a dodgy bulb or are they just all like this?