Why it's flagged. Your file uses a style the factory doesn't know, such as "Letter" or "Recipe", and it isn't in your transmittal's Custom styles. Text in it will be set like an ordinary paragraph (or as ordinary text, for a character style). Inspect lists each one once. Your editor's built-in styles, such as Footnote Text or Hyperlink, are never flagged: they need nothing.
How serious. Listed under Worth fixing. It matters only if the style means something, such as a letter set off from the text. If it only changed how things looked in your editor, it's harmless.
How to fix it. In any editor:
- Declare the style in the transmittal's Custom styles, based on one of the factory styles.
- Or apply a factory style instead, such as Block Quote or Verse.
- No styles in your editor? Start the paragraph with a marker, like
[[quote]]or[[style:Letter]], and see Send your manuscript.
When to leave it. If the style is a leftover from pasted text, or only changed how things looked in your editor, leave it. Build a proof to check. In the full report, correct as is stops it being flagged.