Stitches has so much CDR on (Q) Hook it wraps back around and add more cooldown. Helping Hand reduces by 8 Seconds, Level 7 Serrated Edge reduces by 5 Seconds, Level 20 Master Hooker reduces by 5, for a total remaining Cool Down of -2 Seconds which results in Hook actually gaining a 2 second Cool Down when Used.
Base (16sec) - H. Hand (8sec) - lvl7 (5sec) - lvl20 (5sec) = -2sec
There should be a 0sec Cool Down.