So the Rank functions in Tableau are Table Calculations. This means they are not run (in the background on the data) but how it calculates is dependent on the Level of Detail of your Viz and how you set the Table Calculation to compute.
If you right-click on your rank calculation pill (in your Viz), you can see what the 'Compute Using' is doing. When you bring a Table Calc into your Viz, Tableau guesses how you want to run it, but if it doesn't get it correct you can set how to run it here.
So if, for example, the points/marks you want Ranked were Cities, by setting the Compute Using to cities, it should now Rank the Cities. If you have multiple dimensions in your view you may need to do some extra customization.
If you try just changing the Compute Using to the Level of your marks, and see if that works, If not...can post an example of your workbook, and we should be able to get it working