How can 'combat in pending' occur when the rules state that after combat, if the attacker doesn't win, their units are recalled?

Ruling: Combat can be pending when game effects move units to a different battlefield during a showdown, creating an unresolved combat that must wait until the current showdown resolves.

Sequence:

• During a showdown, an effect moves units to a different battlefield
• The original showdown continues and resolves first
• After resolution, the combat showdown at the other battlefield occurs
• During this time, the second combat remains in pending status

Nuances:

• When multiple showdowns are pending simultaneously (e.g., one combat and one open), the open showdown takes priority and resolves first
• Examples include Zenith Blade moving opponent's units during a showdown, or effects like Traveling Merchant creating multiple simultaneous pending showdowns