Wrong kern values in final .ttf


I have a UFO with perfect kern values but when I generate a .ttf from this UFO, strangely some of the kern values get wrong in the final file.

The problem does not happen when I generate a final .otf

Any ideas?
Thanks in advance,

UPM Conversion?

How do you test the file? Maybe a cache problem?

What kind of wrong values do you get?

I think I solved it, I had two different kinds of kerning data.