Sorting not working when report definition is used in repeat grid
I am currently working in Pega 7.2.1.I have a section with a repeat grid whose source is marked as report definition. Allow sorting and filtering is checked in the grid and sorting type and order is also mentioned in the report definition. But sorting is not working, I am getting section not found, it is referring to @base class. Can anyone help me out with the reason for the issue and it's fix, if any.