[Phanx]

Just FYI there is no reason to define variables outside of a loop when they will only be used inside of the loop, and doing it anyway can have unintended consequences depending on what you're using the variables for.

Don't:

    local icon, count, dispelType, expires, caster, spellID, canApplyAura, isBoss
    for i = 1, 40 do
        _, _, icon, count, dispelType, _, expires, caster, _, _, spellID, canApplyAura, isBoss = UnitDebuff(self.displayedUnit or self.unit, i)

Do:

    for i = 1, 40 do
       local  _, _, icon, count, dispelType, _, expires, caster, _, _, spellID, canApplyAura, isBoss = UnitDebuff(self.displayedUnit or self.unit, i)

(Also, your code was leaking a global _ variable, which in the past has caused UI-wide breakage. Be careful about any global leakage, but especially _ and other common variable names.)