Paring Ikea Silverglans dimmer works but disconnects again

I am a moderate experienced user of Domoticz on Raspi 2 + a Conbee 2 device.
Version is 2.12.06 / 19-8-2021
Firmware 266B0700

I can connect my recently purchased IKEA Silverglans dimmer without any issue and it also works in Domoticz, so you might think “what is your issue?”. As the Mrs desired a separate button to control the lights I also purchased an IKEA Styrbar RC. I have played for hours to get them control the lights both by Domoticz and the Styrbar simultaneously. Yesterday I was able to get this working. At least so it seems for a while.
This morning I mounted the lights + the Silverglans driver but the after having all ready I noticed that the Conbee 2 lost contact with the Silverglans driver for some (at that moment) unknown reason. After having investigated why this happened I had to pair the Silverglans driver at the usual way, resetting the device and ordering Deconz to look for lights. That worked instantly. However, as soon as I paired the Styrbar controller directly to the Silverglans driver, the SG driver appeared to be disconnected from Deconz. From that moment the Styrbar RC worked Ok but I need that both devices can control the lights simultaneously.

I really have no clue why this has worked (for a while) but I can’t get it to work again like I want. Calling with IKEA customer-service is useless as they have no clue regarding Zigbee with the Conbee sticks in general.

Yesterday I found a topic where someone explained how he got this working and AFAIK he did this in the way I did this today about 10 times. Unfortunately I can’t find that specific topic anymore to confirm whether I performed the same trick. Exactly like I wish. So using the Styrbar RC shows the Conbee slider to move. Or better, in Domoticz the slider also moved.

In the meantime I gave it up as I can setup it for the 11th or 15th time but the result stays the same. For now, I only use the Styrbar RC so the Mrs is happy. But I still want to have it paired too with the Conbee 2 / Domoticz so any help would be highly appreciated.

Nobody?? :weary: