Describe the bug
This bug does not seem to be specific to 25. it actually seems to be happening on 23 for me as well. It may also be related to an apache2 change highlighted in the answer on this post (that solution worked for me)

The issue is when you upload a file to the document repo with spaces in the name. when trying to re download the file you get a failed-forbidden error message (tested on test VM). Modifying the htaccess file as indicated in the linked post above solved the issue for me at least temporarily.