How to reproduce:
1. Create and open a new project
2. Right click in the Project tab and navigate to: Create > UI Toolkit > UI Document, to create a new UXML file
3. Open the new file
4. In the UI Builder add any element to the Hierarchy
5. Save changes and close the UI Builder window
6. Repeat steps 3-4
7. Right click in the Project tab and select Reimport
8. Click Reload or Ignore
9. Observe the Editor

Expected result: No pop up dialog appears
Actual result: “UI Document was modified externally” pop up appears

Reproducible with: 2022.1.0a1, 2022.3.62f1, 6000.0.50f1, 6000.1.4f1, 6000.2.0b3

Reproducible on: Windows 11
Not reproducible on: No other environments tested

Notes:
- Depending on the Editor version “NullReferenceException”, “ObjectDisposedException”, “Accessing invalid property” and “type is not a supported pptr value” errors are thrown.
- If we follow steps 2-4 then step 7, the pop up will not appear, sometimes errors are thrown