Bear with Set's Mechanic

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

• WWizards of the Coast2019-11-12
  Official Ruling
  As your first combat phase ends during your turn, if one or more creatures you control have aggressive, you have another combat phase before your second main phase. This is called the aggressive combat phase.
• WWizards of the Coast2019-11-12
  Official Ruling
  If you control no creatures with aggressive as your first combat phase ends, but control one later during your turn, you won’t have an aggressive combat phase.
• WWizards of the Coast2019-11-12
  Official Ruling
  Creatures without aggressive can’t attack during an aggressive combat phase.

Rulings via Scryfall