is this font autohinted?
Just a guess, since there's not much info here, but it looks like the ascender heights are incorrect in application and values, you might want to try generating without autohinting, to see if it removes the problem. Then if it does, try adjusting the hints.

Jason C

Thanks Jason C much, let me try!

BTW are you adding Vietnamese accents to an existing font? If so, here are two things to consider:
1) I think they're exceedingly small - too small to be functional.
2) Most fonts have a EULA (license agreement) that doesn't allow modification; but even ones that do rarely allow you to redistribute the results - so you have to make sure you're the only user of the modified font.

hhp

Hi Jason C, Thank you! It works after adjusting the hints.
hrant: This font is from my client, it does not have VNese accents, so i have to add VNese accents, basing on an Unicode font. Thank you!

You might want to advise your client concerning the risks of redistributing the font.

hhp

I'm glad it worked, but please read Hrant's first post, as he's very right.

Jason

A debt of gratitude is in order regarding this extra data, I truly like this article.
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