My mother wanted my name to be spelled Joni, but somehow it got spelled Jonie on the BC. She said she was 'kind of out of it' after the birth and she didn't catch the error until it was too late. She always spelled my name without the e and when I was old enough to spell and write my own name, I was used to Joni, so I kept it. But, on my DL, Passport, and other documents, like marriage cert, it is spelled with the e.
It seemed to me that the issue with the mother's name spelled (boring, old?) Madeline, where she styled herself as a more cutesy 'Madelyn' was similar to my own story.