If go to http://en.wikipedia.org/wiki/Time_(disambiguation)
your URL is typically converted to http://en.wikipedia.org/wiki/Time_%28disambiguation%29
If copy&paste the last part and try to link to [[Time_%28disambiguation%29]] on a page, this works, but if you try it in an edit summary, the history shows no link, just the plain text "Time_%28disambiguation%29".
This is a problem with all edit summaries that contain character entity references like %28 (so this problem is present also with umlaute and other language specific characters). (Note: this bug might be related to [[Bug:8996]])
Version: unspecified
Severity: normal