Steps:
1. Open attached project (20210909_tes.zip)
2. Open _Texture_PreviewThumbnail scene
3. Hit play
4. Observe GameView

Expected: All three quad looks similar/the same.
Actual: The middle quad looks brighter. The middle quad is using AssetPreview.GetAssetPreview()
Select the texture and observe the thumbnail on top of Inspector, it also looks brighter.

Reproducible:
2022.1.0a8 (a6d7f27874c0)
2021.2.0b1.3027 (1e2674f03162)
2021.2.0a20.2866 (0bd21e314fca)
2021.2.0a19.2770 (f81c6ad18371)

Not-reproducible:
2021.2.0a18.2582 (5605789000ce)
2021.2.0a17.2411 (96ee4da88f82)
2021.2.0a14.1979 (462ae11b66db)
2021.2.0a6.1011 (dc497bf8326a)
2021.1.21f1.3059 (f2d5d3c59f8c)