Decisive Strike not working on first hook

Pyrosorc

Three games in a row today, my DS has not worked after I am tunneled off the first hook. At first I thought I just missed the skill check (weird but maybe I'm just getting old) - except all three times, the DS activated again after my second hook, and I managed to use it again one of those times. A missed DS would not be active the second time, and it was definitely still showing as active (timer still going between 10-30 seconds left) in all instances.