Soft glow in 20.12.1c project renders differently in 22.08.1

Tested with kdenlive-20.12.1c-x86_64.appimage, kdenlive-22.08.1-x86_x64.AppImage on Ubuntu 22.04.

To reproduce:

1. Open effects-stylize-20.12.1.kdenlive from erjiang/kdenlive-backcompat
2. Render out the project in both versions listed above
3. See that the final section of the video looks very different - the soft glow in 20.12.1c looks instead like a flat brightness across the entire frame.

Looks like the blend option changed between the two versions - maybe that's related?