A new Pokémon Sleep update, version 3.3.1, is now live and focuses on a round of bug fixes affecting several mechanics and Pokémon. The patch addresses issues tied to Main Skills, including problems with Metronome, Transform and Mimic skill copy interactions. It also fixes bugs involving Heracross and its Bulk Up Cooking Assist S skill, along with Darkrai and its Bad Dreams Charge Strength M ability. In addition, the update resolves problems related to the Snapshot Surprise feature. While the patch does not introduce new content, it aims to smooth out gameplay and improve stability, so players should download the update from their app store to keep the experience running properly.
Source: Official Pokémon Sleep news