How to reproduce:
1. Open attached project (RenderMode_Dropdown_Test_Project.zip)
2. Select the "Light" GameObject in the Hierarchy
3. Select the "Canvas" GameObject in the Hierarchy
4. Open the "Render Mode" dropdown on the Canvas component in the Inspector

Expected result: The dropdown displays the Screen Space - Overlay, Screen Space - Camera and World Space options
Actual result: The dropdown displays the Auto, Important and Not Important options

Reproducible with: 2019.3.0f4, 2019.3.2f1, 2020.1.0a17, 2020.1.0a23
Not reproducible with: 2017.4.36f1, 2018.4.17f1, 2019.2.20f1, 2019.3.0f3, 2020.1.0a1, 2020.1.0a16
NOT reproducible with 2020.2.a1

Notes:
1. Tested components with a "Render Mode" dropdown affected by the issue: Canvas, Light, Video Player
2. Particle System component not affected by the issue
3. When a "Render Mode" dropdown is displaying options from a different component, if the amount of items in the dropdown is less than or equal to the number of items there should be for that component, the items have different names than what they should, but work as intended
4. If the "Render Mode" dropdown is displaying more items than the component should have, any item selected that has an index greater than what the maximum for that components dropdown should have, causes the following error to be thrown in the Console:
enum index is out of range
UnityEditor.PopupCallbackInfo:SetEnumValueDelegate(Object, String[], Int32)