Does permissions feature on Allow Users to Edit Ranges work?

Just wondering if anyone was able to get the Excel 365 Edit Ranges permissions to work for different editable columns or cells.  Suppose, I have a worksheet with 2 columns (Column A and Column B) that I want Group A to be able to edit cells in Column A and Group B to edit cells in Column B.  When I did the following config in the Allows Users to Edit Ranges:

1. Set permission to ALLOW users in Group A to edit ranges (Column A) without a password 

2. Set permission to ALLOW users in Group B to edit Column B without a password

3. Enabled the Protect Sheet

The result:  Users in Group A and Group B can edit both Columns A and B which is not what I expected.

The result is still the same when I explicitly set the permission to DENY for Group B's users to edit Column A ranges without a password and Group A's users to edit Column B ranges.  

Not quite sure why it's not working when I tested it in the desktop mode.  Any thoughts or suggestions?  Thank you