Missing span leading to different heading

Evening all,

I have a three column section to a page - How it began, Don’t miss and About us.

Each was created in the same way, but the text on the About us looks bolder and is slightly lower than the other headings.

Everything tallies in the menus: it’s all header 3 etc, etc.

Then I noticed that when I pass my mouse over the type, I can see “Span” come up in the “correct” headings but not in the one that looks wrong.

Any idea for a solution will be welcome.