Before you fork out for Adobe Acrobat, consider instead PDF Creator, which my add-in will also accommodate when present.
PDF Creator doesn't exhibit the problem either. I do however suggest using the older less bloated version of PDF Creator which is linked from my web site. Beware when installing that you deselect all the free junk that comes with it - see the link and warning at
http://www.gmayor.com/MergeAndSplit.htm