Thank you for the repro information. I was able to observe the issue locally and I believe that the unique name of the "Product" dimension (first level) is equal to
the "Product" child dimension (second level) unique name. In other words, the DIMENSION_UNIQUE_NAME of the first level member is equal to the HIERARCHY_UNIQUE_NAME of the second level member - both names are set to "[Product]". Hence the PivotConfigurator always finds the the first level member and requests its hierarchies. What you need to do is to set unique names to every member in order to avoid such issues.
As a side note, the name of the first level "Product" member is "[Product]" and the unique name of the second level "Product" member is "[Product].[Product]". You can examine the response in our online demos
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