In my PBI report I have a calculated table (written in DAX). There is a complex calculated column added to the table. On two occasions, I have edited the DAX in that calculated column, and after ...
I'm seeing something odd as well, it's not exactly the same but it might be related.
When I add a calculation table with YTD, MoM, YoY, etc, every number field, no matter the type loses the sigma icon on the field explorer and won't work in the calculation table. To get it working I need to create a measure to do a sum on that field then use the new sum field.
It's almost like adding a calculation field changes the properties of the entire model...