That’s exactly the situation I do understand- where there is a field for date of birth and a field for date filed and they are not the same. The one I don’t understand is " My birth certificate says I was *born *March 2, but I celebrate on the date I was actually born , February 27 ( which apparently is not mentioned on my birth certificate at all) "
My mother was born in 1931, at home with a midwife present and the time was recorded. The midwife was a neighbor lady who just did that sort of thing, not anyone with a license - if there even were midwife licenses back then. But the birth wasn’t officially recorded until a month(give or take a couple of days) later. My guess is that they were scheduling her Christening and only thought about filing the paperwork with the city when Father Whosit asked about it.