If you have a glossary term that contains another glossary term, it can lead to inconsistent automatic definition highlighting.
For example, Linus might have glossary terms defined for check and price check.
If he uses these terms in the same article, the automatic highlighting won't always behave consistently.
In some cases, it will highlight the shorter term (check) and won't highlight the longer term (price check). In other cases, it will highlight the longer term (price check) and won't highlight the shorter term (check). The behavior depends on the order the terms appear in, how many times it's set to auto-highlight each term, punctuation, and other formatting.
Recommended solution
Manually add both glossary terms using the steps in Add glossary definitions in articles manually.
For example, nocturnal owl is a glossary term. So is "nocturnal". If you hover over the definition earlier in this sentence, you'll see only the definition for nocturnal is showing--not for the full multi-word term.
But I can force this to show the correct definition if I manually insert the nocturnal owl term and definition to ensure it highlights properly (which I've done in this sentence). I can also manually insert the nocturnal definition to ensure it shows properly.
This manual highlighting of multi-word glossary terms should only be necessary when you have other glossary terms that contain a portion of that term, or when you want to include highlighting for a term that doesn't match exactly, such as nocturnal owls.