This update primarily targeted several glitches that could disrupt gameplay or be used for exploits:

Corrected an issue where items could sometimes be given to Pokémon Eggs. Installation for Modded Systems (CIA)

Patched a well-known glitch that allowed players to complete all Poké Pelago activities instantly by manipulating the console's calendar during a month change.

Fixed a bug that sometimes prevented Scatterbug from properly learning Egg Moves.

Update 1.2 for Pokémon Sun on the 3DS is a significant patch released to address critical bugs and is required for all online features like trading and battling.