ok, So I managed to fix the issue.
Posting this for anyone else who might face this issue in future.
Cause:
After the fight, I noticed that the icon for the "vulture leggings" had changed as well as the cosmetic for character had been updated.
Solution:
I checked my file in GIed (DOS 2 save game editor -
https://github.com/NovFR/DoS-2-Savegame-Editor/releases ) and compared it with an old file, and turned out the "template" had been updated for the "vulture leggings". In my reference file, there was only default template and no template update- so that was my hint for trying this out.
I took the option for "apply original template", saved the file.
Reloaded the game and noticed that the correct texture was in place for the "vulture leggings", but didn't yet have the missing skills.
Re-equipped the legging and voila! it worked.