Getting a Question Mark

On our site https://www.belmontanglican.org.au/ We have been using the dictionary for some time. Recently is has stopped delivering the tooltip when you mouseover or hover a term but generates an outline of a question mark. We have quite a few terms https://www.belmontanglican.org.au/education/glossary/ so it is a bit of a shame it has stopped working. It is working on another site, so I am not sure where the problem will be.

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