This may take a few steps, but I think you can get there.
First, I created a Custom date for the Date field:
Not necessary, but I think it makes it easier.
Then I used a lookup type filter so that the previous month's data is isn't filtered out:
LOOKUP ( ATTR ( [Order Date (Days) ] ), 0)
This uses the method described here:
Then compared this to the Max Day:
LOOKUP ( ATTR ( [Order Date (Days) ] ), 0 ) = WINDOW_MAX ( MAX ( [Order Date (Days) ] ) )
Placed that on Filter shelf and selected True.
Please see workbook v10.3 attached in the Forum Thread.
285535date.twbx 1.2 MB