"I purposefully chose to create a nearly identical username to an existing user" isn't a great defense to someone saying the problem is between the chair and keyboard.
At best you didn't think of the possible confusion you'd cause.
So sorry, but no. Things have been fine. In places where the hyphen is ambiguous, I always make a point to mention it. It's never really been an issue, and the other individual has always been quite nice when the hyphen is omitted, kindly pinging me instead.
I'm not trying to defend against anything except poor attempts to paint me as somehow malicious...
Is that even surprising? Some names are just so common that people use them all the time and ends up as John, John_ , John-, John1, John11. John100
I don't really see what problem using a hyphen in a username could pose, unless there's some kind of filter being applied that doesn't take into account the previously permitted characters. I'd guess someone applied an [A-z0-9]+ without thinking too much about it because that's what the current username rules are.
I'm more surprised that there's a second authorization endpoint, Github could've just used their existing OAuth2 implementation to log users in if they didn't want to reuse the existing login code.
`[A-z]` -> https://regex101.com/r/IlhPiD/1 `[A-Za-z]` -> https://regex101.com/r/iWjwf2/1
After looking it up, `\p{L}` looks like it matches letters https://regex101.com/r/1UiG9S/1.