Reproduction steps:
1. Open the attached project ("1225501.zip")
2. Open "Scene"
3. Enter Play mode
Expected result: Terrain GameObjects are redisplayed at the same speed as before
Actual result: Terrain GameObjects are redisplayed noticeably slower than before
Reproducible with: 2019.3.0a9, 2019.3.6f1, 2020.1.0b2, 2020.2.0a4
Not reproducible with: 2017.4.38f1, 2018.4.19f1, 2019.3.0a8
Notes:
- In this scenario, there are 7 terrains which are all being setActive(true) in an IEnumerator that is used as a coroutine
- The trees used on the terrain are the Broadleaf_Mobile from Standard Assets
- In the versions deemed not reproducible the same action would take 15-30ms, while in the versions deemed reproducible it would take 500-1000ms