I think everyone who said Regina had a connection with Tink could be right. Also, “A Common Fairy” seems to mean Tinkerbell didn’t make the final cut of being a fairy godmother. Or it could mean that she isn’t at all common despite PP saying so in the original story.
That makes me think Blue and Tinkerbell might have been rivals for being fairy godmother but Blue got it and Tinkerbell being Tinkerbell, went into a fury and got banished to Neverland.