Table of Content macro picks up text "Content by Label" when the Content by Label macro is empty (no pages with label)

When using the Table of Content macro along with the Content by Label macro on a page, the Table of Content macro will pick up the Header "Content by Label" if the macro is empty - no pages with that label.

To reproduce:

• Create a page in Confluence
• Insert a Content By Label macro with one label which no page is using
• Insert a Table of Content macro
• Click save, and you will see "Content by Label" (pulled from the text when the macro is empty)