In erm/eusage/usage_data_providers the date picker for data harvesting (begin and end date) should not ask to choose a day, only a month and a year. The day have no meaning in the context of sushi protocol. I have only checked in 24.11
Maybe I am wrong, I see that... https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=41182 But in other ERMs I know the user is not supposed to choose a day