Reproduction steps:
1. Create a new project
2. Import the “CustomToggle.cs“ Script to the Project’s Assets folder
3. Observe the Console

Expected result: No errors are present 
Actual result: “A UxmlElement for the type CustomToggle in the assembly Assembly-CSharp was already registered from another assembly Assembly-CSharp.“ Error is logged

Reproducible with: 6000.0.5f1,
Couldn’t test with: 2021.3.39f1, 2022.3.32f1 (due Script errors, missing features)

Reproducible on: M1 MacOS 14.4.1
Not reproducible on: No other environment tested

Note: This error does not prevent playing in editor or building the project or otherwise interfere with expected functionality, it just clutters the console window after each recompile until it is cleared