Yup. In 7.5.8, the UBB.Threads developers changed the way "Spider-Friendly URLs" were generated. That change not only caused search engine indexing problems (due to the special characters being placed in the URLs) but it also generated "duplicate content" flags to be raised in Google's Webmaster Tools dashboard. (
some further reading on that)
Since UBBT 7.5.8, here at some other things that get placed in the URL which should not be there:
? > < " & + | ! % # \ ^ { } = : ; @ $
See here for a fix:
https://www.ubbdev.com/forums/ubbthreads.php/topics/319241
