When reloading a session (battle), the game only activates summoning abilities like Drought, Intimidate, etc if they meet one of these 3 criteria:

• The battle is a trainer battle.
• It's the first wave of a biome for classic mode standards (1, 11, 21, etc)
• The battle wasn't loaded from the menu

This logic doesn't include all scenarios where summoning abilities should trigger, like going from a single to a double battle or changing biomes in endless where it can happen on nearly any floor.

It's also built on a flaw: When reloading a session, all Pokemon on the field are sent out, including the ones who were supposed to already be there.

To fix this issue, I propose storing the current allied Pokemons on the field when saving a session. Then, when loading it, only activate summoning abilities of the Pokemon who weren't on the field when the session was saved.

This, together with #694 should fix most if not all bugs pertaining to reloading sessions.

Drought and Psychic surge are both activated when switching biomes in endless:

After reloading the fight neither activate: