I believe this is a bug. With hyphenation turned on within Publisher, words separated by a slash seem to get treated oddly. For example, and/or at the end of a line is hyphenated as an-d/or, fast/slow as fast-/slow, he/she isn't hyphenated in any way, and longer words separated by a forward slash like anthropological/archaeological seem to break in all the logical places (and won't break at the slash).
This is with default hyphenation settings. I didn't see any settings that seemed relevant.