Seems I did the mistake. Bug appears only when cancelling rename by pressing F2. Sorry for spending your time.
So, try to reproduce it with next steps (almost similar you did):
- Create A material and a material instance to be renamed
- Select First Material and press F2 to highlight name F2_2
- Press the Esc key to cancel renaming
- Use arrow key to navigate to next Material (instance) F2_4
- Press F2 to hightlight and rename F2_5
Thanks.