Downloads Truncated names

Moved server from 5.1.4 to 5.1.5 and now people complaining that download filenames are truncated.

For example:
http://www.otherminds.net/downloads/other-minds/other-minds-magazine-issue-01.pdf/view

Download file name is "Other Minds Magazine Issue" without the issue number of the .pdf extension. Should be "Other Minds Magazine Issue #1.pdf".

Any ideas how to fix this?

Thanks!

Never seen this behavior and I can not confirm it (tested with 5.1.5, 5.2-latest).