So I also would say that both Expressions should do the same.
The strange thing is that I´m using Qlik Sense and I´ve a situation (with a pivot table and a drill down dimension) where I get different results. (I know that I´m in the wrong forum for that, but set analysis is the same in both products).
For the moment it´s ok for me, just wanted to have a third opionion. Now I have to do some further checks.