Calendar dates not populating correctly

[Excel Fox]

The formula you are using is an array formula. The reason why it was repeating the same dates for each row was because of the transposed numeric array {0;1;2;3;4;5} that was meant for each row.

So in your case, you should split this formula in to 6 individual rows, each with seperate row index, with the first index starting with 0.

=IF(MONTH(DATE(YEAR(I1),MONTH(I1),1))<>MONTH(DATE( YEAR(I1),MONTH(I1),1)-(WEEKDAY(DATE(YEAR(I1),MONTH(I1),1))-1)+{0}*7+{1,2,3,4,5,6,7}-1),"",DATE(YEAR(I1),MONTH(I1),1)-(WEEKDAY(DATE(YEAR(I1),MONTH(I1),1))-1)+{0}*7+{1,2,3,4,5,6,7}-1)