When saving a report that contains a URL action to PowerPoint, the action is lost if there is no value within the textbox. If there is a value within the textbox the URL action is then attributed to the value and the URL can be accessed with a Ctrl+Click command, on the text value not the text box.

The above screenshot shows a textbox with the word Test included in the textbox, this word has the URL action, if this word is removed when the report is exported to PowerPoint the URL action is not included.