The name BATTLETYPE_SHINY gave the impression that it applied to all battles with Shiny Pokémon, rather than merely battles with forced Shiny Pokémon (i.e. Red Gyarados only).
Hmm. This is the first time I've ever heard of such a confusion, but on the other hand, BATTLETYPE_FORCESHINY would be consistent with BATTLETYPE_FORCEITEM. Can you update this to use that name?
The name BATTLETYPE_SHINY gave the impression that it applied to all battles with Shiny Pokémon, rather than merely battles with forced Shiny Pokémon (i.e. Red Gyarados only).
Due to recent discussions, this misconception about the meaning of BATTLETYPESHINY came up a few times. See https://bulbapedia.bulbagarden.net/wiki/Talk:Escape#How.28not.29_to_flee for one example.