Reproduction steps:
1. Open project in "Swappy Shapes.zip"
2. Open Console window
3. Enter Play Mode
4. Click on the settings icon on the top right of the Play Mode window (Note 1)
5. Move your mouse cursor above "Reset Progress" button

Expected result: OnPointerEnter and OnPointer exit are called once upon the mouse cursor entering or leaving the area of the UI element
Actual result: OnPointerEnter and OnPointer exit are called very frame when the mouse cursor is moving above the area of the UI element

Reproducible with: 1.0.0-preview.13 (2020.2.1f1), 1.0.0-preview.14 (2020.2.3f1, 2021.1.0b6) (Note 2)
Could not test with:
2018.4.31f1, 2019.4.20f1 because of invalid package dependencies (UIElements Native was missing and I was not sure how to import it back)
2021.2.0a4 because of missing namespaces (I could not resolve this in package manager)

Notes:
1. Sometimes the UI does not respond to clicks. Reloading the scene usually helps
2. A video is attached 2021-02-11 12-19-31.mp4 (383.8 KB)