Whenever I get "Spell Disrupted!" from missing a concentration check either via Web or an AoO, my Sorceress loses 2 slots from her available spells. So for example with 5 available first level spells, she cast Magic Missile and gets disrupted, she is then left with only 3 first level slots. Is this a known bug for ToEE or an obscure 3.5 rule I have just never noticed before?