Problem with glyphs spacing and position in an Arabic font

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:
ezgif-7-646984e7d3

in illustrator, however, when I change the kerning from (auto) to (optical) it looks fine (the default is auto)

ezgif-7-7c7d07e1f9

kerning has no effect on the issue, removed it entirely. played with the sidebearings too with no result

Can you check if you have made some kerning in LRT mode?

Well, I thought I deleted every kerning pair ( I did it in edit mode). After your comment, I checked the kerning window while in the font panel I found a lot of pairs, and these specific letters had weird numbers, deleted and problem solved!
thank you