'Assertion failed on expression: 'GetPropertyPath().empty()' errors are thrown when unparenting children in UI/main stage

Steps to reproduce:

1. Create and open a new project
2. In Hierarchy, 'Right-click -> UI Toolkit -> Standard Elements -> Visual Element'
3. Duplicate the Visual Element
4. Parent it to the first Visual Element
5. Unparent it
6. Observe the Console

Actual results: "Assertion failed on expression: 'GetPropertyPath().empty()'" is thrown

Expected results: Nothing is thrown

Reproducible with versions: 6000.6.0b1, 6000.6.1f1, 6000.7.0a6

Can’t test with versions: 6000.0.82f1, 6000.3.23f1, 6000.5.11f1, 6000.6.0a7 (No UI stage in Hierarchy)

Tested on (OS): Windows 11 Pro (25H2)

Notes:

• In 6000.6.1f1, UXML requires saving for the error to be triggered
• Elements seem to get reparented successfully
• UI Builder is not affected
• Main stage and UI stage are affected
• Also often happens when Creating Templates with Elements that have Parent-Child relations