glossaries package FAQ
The most likely reason is that you are using one of the list-type glossary styles which put the term in the optional argument of \item which sets its argument in bold. The tree-like glossary styles also make the term bold. You can override this by redefining \glsnamefont. For example:
Last modified: 2013-12-08 16:39:19.
Category: glossaries package
Topic: Unexpected Output in the Glossaries