Constant interpolation in animation curve points appears to prevent material updates after hitting apply

When changing the key interpolation of a material curve in an animation to constant it appears to break the updating of the material after the changes are applied. Until the changes are applied it appears to be working as intended.

Regression: Yes, this appears to have been working in the 4.21.2 - 4753657 release version of the engine

1. Download the attached project
2. Open the project
3. Open the "untitled_Anim"
4. Modify one of the keys in the curve (The cube should start changing colors)
5. Click Apply

Result: The Cube stops changing colors
Expected: The cube would continue to change colors due to the change in the scalar parameter that is used in the mesh's material

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