Do hooks need to be specified in the schedule of scheduled pipeline runs? I just had a pipeline run via scheduler and a hook I expected to trigger didn't. I'm trying to diagnose.

Do hooks need to be specified in the schedule of scheduled pipeline runs?

Nope

I just had a pipeline run via scheduler and a hook I expected to trigger didn’t.

hmm, you didn’t move the pipeline or anything right? One possibility is that the entry in the cron tab points at the wrong place somehow