This cannot be reproduced on any platform. This is a machine-specific issue.
I have just tried this on Windows 10 without any problems: I can change folder and file names on the Save As dialog, both by right-clicking and selecting Rename, and by 'left-clicking and waiting' on the name.
Typically, these issues are caused by third-party applications, especially file management utilities that install explorer extensions. If you are using utility software provided by your computer's vendor, or have installed a file management application to extend the capabilities of Windows Explorer, then you know a probable cause for this. On Windows, bloatware causes all kinds of problems, like these or even much worse.