Thanks for a more complete/accurate description of the problem.
Moodle version?
Me thinks you have some table sluething to do ... need to find the tables for game/crossword and how those are linked/indexed, etc. with the tables for glossaries.
There is no Moodle Admin UX for such things so you'll have to use the mysql client and the DB for your Moodle.
mysql> show tables like '%glossary%';
will list:
| mdl_glossary |
| mdl_glossary_alias |
| mdl_glossary_categories |
| mdl_glossary_entries |
| mdl_glossary_entries_categories |
| mdl_glossary_formats
I don't have game installed on any moodle I admin right now so you'd have to do the same type of query for 'game' I would imagine.
There is some table in games that references glossaries.
I do have a 'sandbox' 3.4,.5,.6, and .7 sites.
Could install game on which ever is compat. That's why the question about Moodle version above.
If you could share a link to a no user backup of a course that had game and glossary in it, then I could look into it further.
Could PM me that info ... url to acquire the no user backup and version of Moodle ... and I'll take a look see.
'SoS', Ken