Jem Lightfoote, Sky Explorer

• WOTC Official Reminder Textofficial rules
  Vigilance — Attacking doesn't cause this creature to tap.

• WWizards of the Coast2024-04-12
  Official Ruling
  At the beginning of your end step, Jem Lightfoote’s ability will check to see if you’ve cast a spell from your hand this turn. If you have, the ability won’t trigger at all. If the ability does trigger, it will check again as it tries to resolve. If you’ve cast a spell from your hand since the ability triggered, the ability won’t do anything.

Rulings via Scryfall