After I moved the majority of my Ikea devices (save 2) to deconz, all is super stable.
I now have: (all lights and wall-plugs are Ikea, switches a mix of Ikea 5-button, HUE and Mi Cubes)
12 switches (remotes), 2 sensors and 33 lights/wall-plugs on conbee/deconz,
28 lights and a sensor on a Philips HUE Bridge
More here.