Five of the six letters C, E, H, L, Q, V answer to a single rule; one of them does not. Which is the stray letter?

The step should grow by one at every stage: C 3, then +2 to E 5, +3 to H 8, +4 to L 12, +5 to Q 17, and +6 to W 23. The last term given is V, at place 22, one place short of W, so V is the faulty term. Q, L and H each stand exactly where the growing step puts them, and look doubtful only if the step is misread as a fixed one.