How to reproduce:
1. Create a new Unity project
2. Go to Window -> Package Management -> Package Manager -> Unity Registry -> ECS -> Install
3. Go to Window -> Entities -> Systems
4. Enter the Play Mode
5. In the Systems window, right-click on any column and observe the results
Expected results: The columns have names in the context menu
Actual results: The columns are called "Unnamed Column" despite having a name
Reproducible with: 6.5.0 (6000.5.0a5)
Can't test with: 1.4.4, 6.4.0 (No context menu)
Reproducible on: macOS Tahoe 26 (M1)
Not reproducible on: No other environment tested