Priest Spells suddenly inactive

in Not An Issue
Both my priests (Viconia and Anomen) had their spells go grey just after buffing for the temple fight after the dragon in the Elven city. What did I do and how do I fix it?
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Comments
"Champion's Strength (Casting Time: 2 Duration: 3 rounds/level) ALT.
What it does- Grants to the target a THAC0 bonus of 1 every 3 levels & adjusts
the target's strength to 18/00 (even if it was higher before).
Usefulness- (3) Sounds great, but the major drawback to this spell is that the
priest is unable to cast any other spells for the duration of this spell."