Does a unit heal after dealing damage with challenge when a showdown ends if it's not in the same battlefield?

Ruling: Yes, all units everywhere heal at the end of combat, so a unit that dealt damage with challenge during a combat showdown will heal even if it's not in the same battlefield.

Nuances:

• This only applies to combat showdowns, not standard showdowns
• The healing occurs at the end of combat regardless of the unit's location