Sorting on report columns is not working

I’m on v11.1.20 (master) and when I want to sort in a report on a column using the little arrows, the sorting is only working (sort of) on the records on the screen. See attached screenshots where I first sort on a 20 records screen and then on a 500 records.

Also the sorting is not always working as expected especially on dates. See screenshot. I sorted ascending on date and you will see that in the middle the date jumps all at ones to some earlier dates.