Media files with accent characters do not upload correctly to the bucket

Hi. I have a large site with 1000s of media files. Installed wp-stateless. Configured it with CDN mode. Run sync to send existing media files to the bucket. Everything seems fine except for media files that have a special character such as an accented letter in the filename. wp-stateless appears to create a sub-directory named with the special character, and then puts all the wordpress-generated thumbnails inside it. The original media file is placed in the correct directory. But the thumbnails are not. Therefore when the site tries to serve the thumbnails directly from the bucket, it is looking in the wrong place.

For example, if the media file is uploads/2018/06/željko.png (note the accent on the z character). WordPress generates željko-150×150.png and željko-800×400.png and so on.

These get uploaded to the bucket as 2018/06/željko.png which is correct and 2018/06/ž/željko-150×150.png and 2018/06/ž/željko-800×400.png which are not correct (note the subdirectory in the path).

The site tries to access these files without that subdirectory, and therefore can’t find them.

Is this a known bug? I couldn’t find an answer in existing support topics. If you aren’t going to fix this any time soon, is there a recommended method of cleaning up accents in the media filenames so that we can do that before doing the sync to the bucket? I found one plugin that does this but it relies on manually selecting multiple images in the media library and then using the plugin to fix their filenames. My site has thousands of media files so this is not a feasible solution.

Thanks in advance for your help.

Russ