best practice with xlsx files: Git doesn't seem to remember it's tracked when switching branches

[Larry LeFever]

Though I have, for instance, png-files tracked in my repo without issue, I recently started committing xlsx-files.  Each is a template that I programmatically update with data, etc., based on DB-queries, and then either programmatically attach to emails or make available for download.  Anyway, though I have ".xlsx binary" in .gitattributes, and though I've committed and pushed xlsx-files to my repo successfully, when I switch back to the branch to which such files are committed, Git complains about such files being in the way.  If I move them out of the way, the switch succeeds, bringing the latest version of such files into my working-copy.  I diff'd them and saw them determined to be "identical".

I read something (I think, on stackoverflow) about a possible case-sensitivity problem with this, but that doesn't seem to be the problem in this case.

Is there some particular config-setting (or anything else) required to cause Git to consistently recognize tracked unmodified xlsx-files, so I don't have to keep moving them out of the way?