A paragraph in my manuscript is frozen at a very large font

When I try to reset the font size, it does not respond.

Cut and “Paste and Match Style”?


Paste it below the previous paragraph after hitting return at the end of it.

This is likely a paste bug that can happen when pasting from HTML (like a browser). The software isn’t properly filtering out HTML markup in the active session, which can lead to hard-coded behaviours (like what an <h1> should look like), that do not respond to editing commands. Another symptom of this can be phantom links, particularly those that arrive from <a id="blah"/> anchors, meant to be there purely as link targets.

These problems typically go away after reloading the project (or potentially leaving the binder item unloaded for long enough that it internally unloads it from memory), where the rogue formatting may entirely vanish, or at least become something that can be modified. It’s not actually stored that way in other words.