"Source and Target" searches within a document are stored in the history token. When a new document is loaded, the search in the history token was not updated.
Searches within one document remain active when a new document is loaded. If the search returns no results in the new document, this can interact with a known issue in which the search box is hidden when loading a new document to make clearing of the search impossible without manipulating the URL.
"Source and Target" searches are now cleared from the history token when loading a different document.
No "Source and Target" search will be active when loading a new document.