buffer is modified after commit

[Juanma Barranquero]

I'm seeing a maddening heinsenbug where, after committing to CVS (via
vc-toggle-read-only) a file visited in a non-modified buffer, the
buffer is marked as modified.

I'm quite sure it is not an Emacs bug, but something in my setup (it
does not happen with "emacs -q"; it does happen in my two main
computers without -q).

However, it started very recently (possibly after the unicode merge,
though I'm not really sure), and so far it has resisted any attempt to
locate it via bisection of .emacs. All I know is that it seems to be
related to diff switches, i.e.,

   diff-switches
   vc-cvs-diff-switches
   vc-svn-diff-swtiches (I don't know why, because there aren't .svn
dirs in the tree)
   the setting of `diff' in ~/.cvsrc

Has someone seen something like that, or can anyone shed any light on it?

             Juanma