SSAS discretization groupings and PBI Desktop

Hi All,

Firstly, I have worked around this in the past by creating my own 'Bucket' tables in my data warehouse and simply treating as your run of the mill 1:many relationship when building the cube.

But running the Adventureworks SSAS Multidim cube tutorial, I was playing with: https://msdn.microsoft.com/en-us/library/ms169778.aspx

Which details playing with the DiscretizationMethod and associated properties.

My question as a matter of curiosity:
This feature works fine when linking my cube to excel:

then when i link exactly the same cube to PBI, without changing a thing, PBI errors complaining about the composite key used:

Has anyone encountered this in the past and what was the solution?

Thanks,

Andrew