A new document starts with it off and an import adopts the file's own
flag, so an editor left recording no longer marks the next document it
opens. Both formats carry it, probed against soffice: ODF on the change
registry (text:track-changes, written for the flag alone where nothing
is recorded yet), Word as w:trackRevisions in settings.xml — LibreOffice
writes and reads exactly those two, and reading w:trackChanges instead
would have found nothing.