This bug is only in the JSPUI. XMLUI is unaffected.
If a Bitstream has a semicolon in the file name (e.g. "my;file.pdf"), then the file cannot be downloaded from the JSPUI. Clicking on it results in an error (and the semicolon seems to be treated as a path separator). Here's an example of the error that would be returned for the "my;file.pdf" bitstream:
The identifier "my" does not correspond to a valid Bitstream in DSpace.
This bug was validated on the demo site, and was also reported in this dspace-tech email thread: https://groups.google.com/d/msg/dspace-tech/6MeojM5ZcC8/1hzPAGo1CgAJ