When working MS Powerpoint or MS Excel files, it has been observed that filenames upon saving can change capitalization to lower case. So, for example, if a user is working on a file named MyTestFile.xlsx upon saving MS Excel, may change this name to mytestfile.xlsx. Such behavior was observed only with MS Excel and MS Powerpoint files only. This issue has also been reported to Microsoft, but no fix has been provided so far.
Suggested Approach / Workaround
Until Microsoft fixes the MS Excel and Powerpoint issue, the only viable solution is manually renaming the files with proper capitalization. Such change will not be reflected as a creation of the new version of the file.