When you upload a document you can add Metadata. We use the Term Store for labeling our document. When adding a term sometimes the corresponding terms are found and marked yellow. But not all terms are found and highlighted, although the do excist and can be added.
In the attached image you see the first term highlighted. The second term is not, but is present in te term store and can be added to the document.
When searching for a term, Email Manager should automatically highlight any items that match the entered text. However you will still be able to select other terms that are not highlighted.
From what I can see in the screenshots provided, the highlighted terms are correct based on the search criteria. However, the window is cut off.
Are you able to provide a larger view of your list of terms showing the items that are not highlighted as anticipated?