SYNOPSIS:
If you have a page with a 'Table of Contents', any anchor links with a URL containing certain special characters will be broken. For example, if any of the following appear in a Header, the corresponding link in the Table-of-Contents will not work: ampersands, colons, commas, double-quotes, equal signs, forward-slashes, parentheses, single-quotes.

Note that dashes in a header do not cause any problem.
I have not tested asterisks, at symbols, carets, curly braces, dollar signs, exclamation points, reater-than signs, less-than signs, percent signs, periods, plus signs, question marks, square brackets, underline aka underscore characters, verticle bars, nor single or double-byte foreign characters (e.g. the Euro or Yen sign).

SNAPSHOT: Please see AtlassianConfluenceSpecialCharsBug.png

ENVIRONMENT: Firefox ESR 17.0.8 on a 64-bit Win 7 Professional

WORK-AROUND:
The work-around is easy enough-- remove the special characters.