Assertion failed on expression: 'didInsert' error is encountered on clicking 'Color Gradient' Field after Enabling 'Multiple Elements' Checkbox in Lens Flare(SRP) Asset.
Refer to the attached Video.

Steps to Reproduce:
1 Create a New HDRP/URP Project
2 Project>Create>Lens Flare(SRP)
4 Inspector > (+) Add to List > Enable 'Multiple Elements' Checkbox > Color Gradient

Actual Result:
"Assertion failed on expression" errors in Console

Expected Result:
No errors in Console

Reproducible with:
2021.2.0b1 (HDRP-12.0.0)

Note:
Lens Flare(SRP) Asset was introduced in 2021.2.0b1

Environment:
Windows 10 only