Hi 
Yes my switch is set to momentary mode as my physical button is momentary. Should I switch it to toggle?
I will try to add logs as soon as this problem happens again.
Yep, that’s probably your issue then. Set both switches to toggle and you should be fine
Hi Shadow Fist,
Unfortunately changing switch type from momentary to toggle didn’t solve the problem 
I got error
z2m: Publish 'set' 'state' to 'Osw_Pietro_18_19' failed: 'Error: ZCL command 0xa4c138423fd4eeb2/2 genOnOff.off({}, {"timeout":10000,"disableResponse":false,"disableRecovery":false,"disableDefaultResponse":false,"direction":0,"reservedBits":0,"writeUndiv":false}) failed ({"target":13145,"apsFrame":{"profileId":260,"clusterId":6,"sourceEndpoint":1,"destinationEndpoint":2,"options":4416,"groupId":0,"sequence":115},"zclSequence":214,"commandIdentifier":11} timed out after 10000ms)'
Below screenshot with logs.
And the light started oscilating. I have no clue what might be wrong.
My physical switch is a momentary push-button type (as ringbell pushbutton).
That Many to one error is…weird. I’m not familiar with it, but it sounds like network congestion.
You might have to look it up to see what it really means. I suggest you start from the Z2MQTT GitHub.