Hi Gwynfor,
This should not happen. Just tried it on my local moodle 1.9.7 and everything works as expected.
Glossary entry: AI = Artificial Intelligence, link to whole words
Glossary entry: offensive = can cause offence
Resource text: Welcome Use your login details and password to access the material. Please do NOT post anything offensive or illegal.
Only word that is highlighted is offensive.
I expect that that text is on your site's front page and you have a front page glossary with AI, ER, etc. entries in it?
Please message me (see my profile) and give me temporary access to your site so I can check.
Joseph
EDIT.- Are you absolutely certain there is not another Glossary with AI, etc. entries in it, not set to "whole words", which the highlighted words in your text would point to?