Repro steps:
1. Create a VFX and expose a Vector3.
2. Drag it to the scene and duplicate it a couple of times.
3. Add different values to each instance (i.e. (1,1,1) , (2,2,2), and (3,3,3))
4. Multi-select all 3 VFX, and change the X value of the exposed Vector3

Expected outcome:
Only the X value will change, the Y and Z will remain unique for all effect instances.

Actual outcome:
The X value changes, the Y and Z value are set to 0.

Note:
- An exposed Vector3 in a C# script when multi selected will only modify the one component of the vector which is changed.
- Happens on many/all vector types (Vector2, 3, the components of an OrientedBox, etc.)
- Not a regression, repros in 6.9.0