My father’s name was changed not long after he was born. He and all his siblings had two middle names, and Dad, born in 1929, was named Herbert. So many people asked if he was named for the president that his birth certificate was amended and the names switched around. He became Harold Harry Herbert Surname instead.
So it wasn’t a spelling change but there was regret.
Has the name been spelled ‘Issac’ in the past? Maybe a name passed on through generations until someone couldn’t stand dealing with the misspellings anymore.
Yet they sell little ‘Bort’ license plates at gift shops.
My fathers name was/is Rudy for Rudolf. My Wife thought it was Rooty. 
My last name is only 4 letters, but can be spelled 3 different ways that are pronounced exactly the same. Homophones I just spell it when ever I give it out. Sort of SOP for me.
But at least it’s only 4 letters.
I just ran across a Synnamon yesterday.
A former co-worker has a nephew named Ruckus (yes, as in “disturbance or commotion”).
That’s it! I’ll name my baby Regret.
“Come her my little Regret!”
“Boy! You’re getting to be such a big Regret!”
I wanted to name my daughter Lizard. Of course she’d go by Liz. But when people would ask if it was short for Elizabeth, she could honestly answer, “no, Lizard”.
I’ve long said that if you must give your baby an unusual name, pick one that shortens to something common. For example, Max is short for Maxwell but is also short for Maxfield, Maximilian and Maximus.
Perhaps more on point, Meg Griffin’s first name is not Megan. It’s Megatron.
Now the Buddha named his son Rahula. According to the Encyclopaedia Britannica, this means “fetter”. However, in any case, “Rahul” is quite a popular name.
I knew a guy whose parents put a comma in his name–not an apostrophe, a comma. When he grew up, he legally changed his name to remove the comma.
I once went on a date with a woman who had a son named something like “Kaeden.” Asked her where it came from and she said it was made up, and she just liked the sound of it.
My adopted brother’s middle name was originally “Daekota.” His mother wanted it to be “Dakota” (for reasons unknown) but didn’t want him to feel dumb by having the syllable “duh” in his name. I kid you not. When he became my brother, my parents changed it to David and corrected another spelling mistake his mom had made in his first name while they were at it.
I wonder if we have the same surname? Mine is also four letters and a dirt-common Anglo-Celtic name everwhere in the English-speaking sphere (not quite as ubiquitous as Smith or Brown, but in the next tier down; I can think of a handful of famous examples, including a senator, an actress, and a porn star.). Yet in the 250 years my family’s been in this country, it’s been spelled five different ways.
My brother is a 3rd and he’s always gone by Trips. But never in public, it’s only a family name. There’s plenty of variations on “Robert” that they could have called all three guys something different but they all just went by Bob (except Trips, at home).
Micheal, Michael I’m always misspelling it. Odd to write ael imo.
I have seen Schuyler spelled “Skylar” !
A friend of mine’s first name is Atarbes. I asked him why his parents gave him that name. He said, “They wanted to give me a name that no one else had. So they simply made it up.”
His parents wanted to raise a Ruckus. Along with his brother Cain…
There was a character on the TV series “Star Trek: Enterprise” named Trip Tucker; his full name was Charles Tucker III, and so, nicknamed “Trip” for the same reason.
It doesn’t seem as common now as it was in the 70s, when I was growing up, but every Trey I ever knew was (Actual Name) III.
There have been quite a few Treys in the NFL in the past couple of decades, and while most are “thirds,” a couple of them, such as 49ers QB Trey Lance and Bengals DE Trey Hendrickson, appear to have Trey as their given name.