What defines whether a spell is a spell or a disc?

[Caryatis]

I just recently updated my server from 1350 to 1450 with the associated required DB updates and I had a lot of instant endurance based abilites for melees that prior to updating all properly went to the combat window. However after updating, the majority of those are now scribed into spellbooks which makes them useless to classes without books.

Which field defines whether a spell goes to the book or the combat windows?