In Riftbound, when Player A attacks an occupied battlefield and doesn't activate anything, and Player B (defender) also doesn't activate anything, can Player A then activate something?

Ruling: No, Player A cannot activate something after both players have passed. When the attacker passes priority and the defender passes back, both players have passed consecutively and combat resolves, moving to cleanup.

Sequence:

• Attacker has initial priority and focus
• If attacker passes and opponent passes back, both have passed consecutively
• Combat resolves and moves to cleanup

Nuances:

• Exception: If there are attacker/defender trigger abilities, priority goes to the person who did not own the triggered ability after the ability resolves
• The defender can play an action when they have priority (after attacker passes focus) since there is no previous action to react to