Namron z-wave dimmer problems

I have recently installed 8 Namron z-wave dimmers ( 1402756) in my house, and they all worked fine for a couple of hours. After that, one by one fell out of my Homey system. Right now only one dimmer is still struggling to keep on with Homey. The only way, as I can understand, to reconnect the dimmers is to do a factory reset and momentary unpower it. But they will still leave the z-wave network after a few hours. How can I solve the problem with these dimmers?

I have the same problem.

Bought 3 of them and one by one they turned off and were unable to reconnect.