It seems that the glossary-filter fails to link synonyms correctly to the corresponding glossary entry. I did not find any other ticket describing this issue, so I created this one. The use of Ajax is activated.
Steps for reproducing the bug:
1. Define a glossary entry "Geogebra-Plugin" and match whole words only and activate case sensitivity (we defined this options as default for our glossary)
2. Define "Geogebra" as a synonym for the entry "Geogebra-Plugin".
3. Now create another glossary entry or forum posting containing "Geogebra" as a phrase and "Geogebra-Plugin"
4. Click on the phrase "Geogebra" and you will get an error, claiming the the search term cannot be found in the database table "glossary_entries", if you click on "Geogebra-Plugin" moodle returns the corresponding entry in an AJAX-popup.
I did not test if the error also exists using the "non-ajax"-view, if you need a further report, let me know.