Complete random/unexplainable z-wave actions

Hi all,

Maybe someone can help me out here.
Sometimes I find devices turning on or a curtain closing without any reason.
It looks like a complete random z-wave action that I cannot explain at all.

In the log , the action is noted but it does not say what triggered it (which is the case if someone or some automation triggered the action)

Anything that can explain this ? Anything I can do to solve this strange behavior ?

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