Niantic has updated the official Known Issues support page for Pokémon GO. Read on below to learn more:
Pokémon appearance duration reduced when moving
Pokémon appearance duration reduced when moving
Issue description: Trainers on version 271.0 or later experienced a reduction in the amount of time a Pokémon would appear on the map when they were moving in the real world. This caused Pokémon to disappear from the Map sooner than expected.
Issue status: Resolved
Source: Official Pokémon GO support page
Known Issues
Issue description: Some Trainers battling may see incorrect or missing visuals if their device has not yet downloaded assets after a new update.
Issue status: Investigating. Please use the “download all assets” feature in the settings menu to mitigate this issue.
Issue description: Some Trainers do not see the ability to change berries or balls when encountering an Ultra Beast in GO Battle League.
Issue status: Investigating.
Source: Official Pokémon GO support page
Source:Pokémon