Sorry about not adding the link. The page you shared is correct but year 1629 is missing. Have shared the coin pics of year 1629 for reference. Thank you.
And a picture of Tibetan numbers taken from the Internet:
I am seeing "16-25", which would be equivalent to 1951 (already on the page in question). I am also thinking there was some sort of die break above the last digit, which could explain what is going on with the top of that character.
I have a 1625 which looks different than the one in question. But as you rightly said, it could be a die break issue. Glad to have an error coin from Tibet, although not a big error. Thank you all for the clarifications.