Reply To: CS5 bizarre auto-numbering problem

OK, I think I've tracked down the problem a little more now.  

In this document there is a single paragraph style for running heads (aligned away from the spine).  The text of the running head should be in roman but the page number should be in bold, so I'd set up a GREP style to apply a bold character style to the page number.  If I delete this GREP style, the problem goes away.  

I'm going to try and replicate the problem in a new document.  I'll let you know how I get on!