Hi,
I've a repository with four subfolders in it and .gitattributes at the root.
When using the following command:

git diff adb8ff70694379ee2d339ef94900b602fa62593c:folder/file.c..cae5dc93450f6d604debfbe832790f0c2968ce48:folder/file.c

The diff is shown but the following warnings are shown at the end:

warning: unable to access 'adb8ff70694379ee2d339ef94900b602fa62593c:folder/.gitattributes': Invalid argument
warning: unable to access 'adb8ff70694379ee2d339ef94900b602fa62593c:folder/file.c..cae5dc93450f6d604debfbe832790f0c2968ce48:folder/.gitattributes': Invalid argument
warning: unable to access 'cae5dc93450f6d604debfbe832790f0c2968ce48:folder/.gitattributes': Invalid argument

version is Git for Windows 2.3.5 release 8.
I've cloned the repository to linux with git version 2.4.6, no warnings are displayed.
I've installed the last version Git-2.4.6-5th on another computer without doing any specific git config, cloned the repository and same warnings are displayed.

I've no warning on Windows when doing:

git diff adb8ff70694379ee2d339ef94900b602fa62593c:.gitignore..cae5dc93450f6d604debfbe832790f0c2968ce48:.gitignore

Thank you.