When she is introduced in Star Wars: The Clone Wars she is 14 years old, and she is 17 when the war ends. During this time, she has short(ish) headtails:
After that, she is shown with medium/long headtails when she is 32 years old in the show Star Wars Rebels:
So WHY are her headtails are so sort in The Mandalorian? (in which she is 45 years old)
I will remind you that Togrutas' headtails continue to grow longer as they get older, and an adult of Ahsoka's age should have much longer headtails than she does in The Mandalorian. Shaak Ti, another female Togruta and Jedi who worked at the cloning facility on Kamino during the Clone Wars, has very long headtails in comparison to Ahsoka's, and she is 40 years old (in this picture)!
This was not an unknowing mistake on the part of the director of the episode. In fact, the director of Chapter 13, "The Jedi" was Dave Filoni himself! Dave Filoni practically created both shows mentioned above, Star Wars: The Clone Wars and Star Wars: Rebels. So it's not like he didn't know how a Togruta should look. He, of all people, should know what Ahsoka looks like!
So, having examined all this, Why does Ahsoka have short headtails?
Is there a canon explanation?