so, I’m testing my font and some weird behaviour appeared with some letter combinations
mainly the reh-ar.fina when one of these letters come after: tehMarbuta-ar, kaf-ar, waw-ar, and reh-ar
the problem appears in text preview, and later on Adobe Illustrator, but all is fine in edit mode
in text preview:
in illustrator, however, when I change the kerning from (auto) to (optical) it looks fine (the default is auto)
kerning has no effect on the issue, removed it entirely. played with the sidebearings too with no result