Why didn't a particular task get pushed?

A task is skipped if: it's in a padlocked (device-only) list; it's already been handed off (it's in the Pushed tasks folder); the list it's in isn't set to push to that app; or it's still being saved. Pushing only sends open, not-yet-pushed tasks. If "Push now" says "Up to date", there was simply nothing new to hand off.