Problem with hanging left margin in 2008

I've noticed an issue with a hanging left margin, as in a bulleted list,
that 
the second line is indented just a small but visible bit too far.

It seems to happen when opening older files from Mac or Windows; new files

are okay. In fact, it can change right before my eyes. For example, say
that 
I open a file someone sent me from Windows. At the start it is okay, but
if I 
type something into the list item, the second line jumps over just a tiny 
bit.

Whether or not there is a tab at the same position as the left margin does

not matter. 

Anyone else see this?