I'm still getting this problem. I have a few Person columns that are single selection only and I am able to exapnd those fine. I have one multi select column which shows as a table rather than a record and I get an error when I try and expand it.
I just want to get a colon separated list of names like you do when you export to Excel.
If I was to use the OData fix, I don't get columns "Managed Metadata" column types returned. If I change the "[ApiVersion = 15]" from 15 to 14 it switches me back to SP2010 which doesn't allow me access to "Managed Metadata" column types either. Setting certain columns to not be null or not multi-select is not an option.
Power BI Desktop version 2.56.5023.942 64-bit (March 2018)
Changing to [ApiVersion = 14] in Source fixed my problem with the SharePoint List column names not updating to the current column SharePoint title when pulling the list into power Bi. Microsoft should fix this for 15!
The problem "Expression.Error:" went away for me if you rebuild the applied steps in the query editor after the Navigation (default name) step. (Note: in ThoSch's code step was called List.)
Well the strange thing is that I have a different list with exactly the same column - multi-select choice - and Power BI is handling it perfectly fine!? So it does not seem to be an issue across the board.