Jekyll - lingering conflict error

The only error I was still seeing after upgrading to Jekyll 4.0 is the following: 
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...
          Conflict: The following destination is shared by multiple files.
                    The written file may end up with unexpected contents.
                    /website/_site/tag/js/index.html
                     - tag/js/index.html
                     - tag/js/index.html


          Conflict: The following destination is shared by multiple files.
                    The written file may end up with unexpected contents.
                    /website/_site/tag/nodejs/index.html
                     - tag/nodejs/index.html
                     - tag/nodejs/index.html

...
It took me a bit of time to figure this one out, but the solution ended up being quite simple -
I was using tags and mixing their lowercase and uppercase (e.g. NodeJS, nodejs, nodeJS).
Once I aligned the tags to be lowercase at all times, this solved all the conflict errors.