Steps to reproduce:

1. Create a new project
2. Open Animation window
3. Select any gameobject in hierarchy window
4. Create an Animation Clip file in Animation window
5. Open the created Animator Controller file in Project view
6. Drag in Animation Clip so there are two of the same Animation clips
7. Make transition from one clip to another (right click > Make Transition)
8. Select the transition line
9. In the inspector hover over the transition timeline and zoom out/in

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Actual results: 

Getting rendering artifacts in the timeline when zooming in/out

Expected results: 

No artifacts when zooming in/out

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Reproducible with versions: 
2022.3.65f1, 6000.0.55f1, 6000.1.15f1, 6000.2.0f1, 6000.3.0a4

Not reproducible with versions: 

Can’t test with versions: 

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Tested on (OS): 
Macbook M1 MacOS Sequoia 15.5

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Notes:

•  Doesn't reproduce if animation clip was created from Project window right click > Animation > Animation Clip