In Qlik, it is best practice not to count on a key field (OrderNr in this case). You can get unexpected results like you are seeing here where you want to count each row, but it is showing only the distinct count and vice versa. If you add a counter field and then sum up that counter field the results will be more predictable. For example:
1 as OrderCounter
Then your expression would be sum(OrderCounter), and it should give you the number of rows on Table2. This should work even if you join tables 1 and 2 in Qlik.