It was observed in the past that the git diff locks the files as well until you quit out of git
And that will not be the case with the Git 2.23
The diff: munmap() file contents before running the external diff
While running the external diff from, the diff tool, it is safe to assume that we are trying to write the files which are in question.
Now on Windows OS, there must not be any other process locking an open handle to the files or the mapped region.
So please make sure that your git diff itself is not holding on any of the open handle to your files in question.