When I use outline numbering in one of many separate documents, the first
level number starts with II instead of I.
I've tried to change it by choosing "Restart numbering" but then all the
other numbering levels before and after disappear.
I've also tried to change it through "Customize" and setting the start to I,
but the same thing happens. All other numbering disappears.
All my other documents use the same outline numbering, and there is no
problem.