Reproduction steps:
1. Create a new project and a new Script
2. Open the script and type UnityEngine.iOS.DeviceGeneration inside one of the methods
3. Inspect the values for UnityEngine.iOS.DeviceGeneration Enum (type "." after DeviceGeneration, the IDE will offer available values)

Expected result: iPadAir3Gen and iPadMini5Gen can be found in the available Enum values
Actual result: iPadAir3Gen and iPadMini5Gen cannot be found in the available Enum values

Reproducible with: 2019.4.29f1
Not reproducible with: 2020.3.16f1, 2021.1.17f1, 2021.2.0b7, 2022.1.0a5

Notes:
1. A screenshot showing the available values can be seen in the Edits