i.e things happen for no cause.
What's the point in asking questions that no one can currently answer?
On second reading, there is cause and effect relationship in QM, it depends on what part of it you are interested in. So it'd be useful if you could ask a specific question on specific QM phenomenon.
Cause and effect is a foundation of classical physics which is less well understood in quantum mechanics. But QM is a less intuitive formulation of physics so casuality may not be as readily apparent. For example, classical causality does not seem to be part of entanglement yet just how it works I don't think is agreed upon.
So I'd rather say that in parts of QM it is not yet understood how causality works.
Different interpretations of QM offer different answers to your question. If you want to have an intuitive interpretation in which causes exist similarly to that in classical physics,
see about the Bohmian interpretation.
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