Has there been a change to the health of Pokémon returning from arenas?

Based on my previous experience and this answer, Pokémon that you left in friendly arenas that got beaten would return to you with 1 hp, thus allowing to heal them directly with potions.

However, today, the two Pokémon that I left in a friendly arena returned to me after some time with 0 hp, which means that I now need revives before healing them.

Has there been any word from Niantic / any external confirmation that this mechanic has been changed, and that now beaten Pokémon always come back to you with 0 hp?

Solution 1:

Yes, Niantic released 1.05 for iOS and 0.35 for Android that implemented this change.

Fixed a bug that kept defeated Pokémon at 1HP; these Pokémon will now return as fainted Pokémon. We’re working on rebalancing the training battle, stay tuned.

Source: https://play.google.com/store/apps/details?id=com.nianticlabs.pokemongo&hl=en