Image styles not generated for images with . (period) in them

On a clean 8.1.0 Drupal site, the image style files in the files/styles directory are generated just fine unless the image has a period prior to the file extension, e.g. file.upload.jpg. Even the little ajax preview that shows up immediately after file upload fails to generate.

I hope/believe this is a core issue and not anything with my setup. I've got the Apache rewrite module enabled and everything, and have the proper permissions on all files and directories.

This also happens on Drupal 8.0.5 and I assume 8.0.6.