On PDF page 909 of the latest JDF spec, Appendix M Release Notes starts with the standard two-ruled-lines with "Appendix M" between. But then on page 914 we get the two lines with "Appendix M" again, in the middle of the table.
I thought maybe it might a function of the large table (6 pages), but in appendix L, the table is 13 pages long and we don't see the "double heading".
The same thing is happening in XJDF as well.
I assume this is just a FrameMaker bug and there is nothing to be done, but I thought I'd mention it just in case. If this is just an unavoidable FM bug, please reject the issue.