When saving a page with a PDF that has been included on the page using the ! exclamation mark, then the error "Failure when converting editor format to storage format" is shown and the page cannot be saved.

Problem only happens if creating the macro with !

Steps to reproduce:

1. Create new page
2. [ +Insert] -> [ Attachment]
3. Attach a PDF
4. Insert
5. Type '!' to embed pdf widget and select file uploaded above
6. Save ("Failure when converting editor format to storage format" error is shown)
7. Remove the pdf widget
8. Save (page saved with no errors)

Workaround:
Include PDF viewer by doing: [ + Insert] -> [ More Macros] and selecting an already attached PDF from there.