This issue has to do with keyboard support, where if the step index is changed programmatically, and then the user tabs back onto the wizard stepper, then the focus class is on the wrong step.  The active step is correct in the stepper, but the focus outline is on the step prior to the programmatic index change.  I have created a repl here:

https://blazorrepl.telerik.com/wcbmlAlj23ZwNsxf21

If you click the Move to 3rd Step button it will switch the wizard to the 3rd step correctly.

Tab to the stepper, and step 1 will have the outline focus class, the focus will actually be on the correct step (step 3).

Pressing the right arrow key will move to Active Step 4, but the outline focus class will be moved to step 2.  

Pressing the left arrow key will then fix the outline class.

I would expect that when changing the step index programmatically, that the outline focus class on the stepper would be displayed for the step that the index was changed to.  It becomes confusing for keyboard users.