To Reproduce:
- Open Unity
- Install Probuilder (Window -> Packagemanger -> Probuilder -> Install)
- Open Probuilder Window (Tools -> ProbuilderWindow)
- Add a cube (New Shape+ -> build)
- Subdivide object (ProbuilderWindow -> Subdivide Object)
- Select face selection in the scene
- Select a face on the cube
- Open UV Editor (ProbuilderWindow -> UV Editor)
- select a face in the UV editor
- select multiple faces in the UV editor - using CTRL
- in the scene, select different faces (5+) than the ones selected in the UV Editor that aren't touching - using CTRL - see Attached GIF(I'm holding CTRL the whole time)

Expected result:
Whilst holding CTRL every face the user click on should be selected

Actual Result:
Only 1 or 2 faces stay selected until the user presses another face which ignores the old faces and just selects the current one

Versions Tested:
2020.1.0a22, 2020.1.0a12, 2018.4.12f1

Platforms affected:
Windows

Platforms Unaffected:
MAC