It is possible that this has to do with your vertical metrics setup and/or the way style linking works in your fonts.
I’d recommend reading Karsten Luecke’s papers on Font Metrics and Na… (View Post)
At least with FontFont® (sic!) it is (or maybe was?) also important to consider that something like FF Legato is a “marketing name”, while the actual font will be called Legato and appear under L in … (View Post)