Unable to sort by labels on Task Report Macro

Issue Summary

It is unable to sort by labels column on Task Report Macro although sorting arrow button is visible on grid table.

Steps to Reproduce

1. Add a page with some task with label 'test1'
2. Add a page with some task with label 'test2'
3. Add a page with Task Report Macro to show tasks in above pages
4. Click the grid table to sort asc by labels

Expected Results

test1 comes first.

Actual Results

test2 comes first.

Workaround

No workaround found at this point.