i have 3 data in 01-May-2020 08:00, 31-May-2020 08:20 and 20-May-2020 18:10.

now, so in June, with filtering that with 1 month ago filter, i get only 01-May-2020 08:00 and 20-May-2020 18:10.

if the filter 1 month ago means 30 days ago, 20May should not be in the results too. And if the filter means the month just before this month like i want, all 3 records must be shown.

What is the problem here?