If a card said 'Stun an enemy unit, then stun an enemy unit', would Leona trigger 1 or 2 times?

Ruling: Leona triggers twice. The word 'then' does not make a difference - unless the same game action is being performed on multiple units simultaneously, the stun game actions do not happen simultaneously and therefore Leona will trigger for each of them.

Sequence:

• First stun resolves and Leona's trigger goes on the chain as a pending item
• Second stun resolves and Leona's trigger goes on the chain as a pending item again

Nuances:

• This assumes the stuns are targeting different units - once a unit is stunned, further stuns on that same unit cannot provide additional buffs
• 'Stun an enemy unit, then stun an enemy unit' is functionally the same as 'Stun an enemy unit. Stun an enemy unit.'
• The word 'then' would need to say 'then do this' to have any meaningful impact
• Prior to version 1.1, this interaction would have only triggered Leona once, as triggered abilities could only trigger after the effect that triggered them fully resolved