exmh_addrs address database truncated

I'm using exmh 2.7.2 and I'm experiencing a really strange problem with the
address database.

Recently, my address database shrunk greatly...even though the option to 
"remove old entries" is off.

I've attempted to "reload" the database by extracting data from messages and 
creating lines in the form:

  set addr_list($ADDRESS) {{$FILENAME} {$RECVDATE} {$NICENAME} {$FULLADDRESS}}

After a bit of clean-up, I've got an address list of 5276 lines. The file 
appears to be syntatically correct; there are no unbalanced parenthesis or 
curly brackets, each line has the correct number of fields, and the $ADDRESS 
values are unique. The file is sorted by $ADDRESS.

For testing purposes, the preferences "Automatic Address Saving" and 
"Checkpoint on Folder Change" are both turned off.

The problem is that exmh only parses and uses a small fraction of the database.

If I stop exmh, copy the desired exmh_addrs file, and restart exmh, it appears 
to load correctly. However, only some of the entries are shown when browsing or 
searching the database. Using the menu choice to "reload" the database produces 
the same results.

If I manually save the database at this point, the exmh_addrs file is
truncated to 375 entries.

If I randomize the line order of the full exmh_addrs, then load it into exmh and
save it again, I get a random number of entries saved...anywhere from 3357 lines
to just 15 lines (out of the original data file of 5276 lines).

For a given input file, the output (ie., after loading the database into exmh 
and then saving to the exmh_addrs file) is consistent. However, the output file 
size varies depending on the order of the input file, and the output file 
doesn't end on the same entry each time.

This leads me to believe that there's something in the datafile that causes 
exmh to stop parsing and internally sorting the exmh_addrs file, but I cannot 
find any lines that are obviously corrupt.

There are no entries in the exmh log that show any errors loading or sorting 
the database.

Can anyone offer more details about:

	the format of the exmh_addrs file

	a syntax checker for the exmh_addrs file

	a way to get more debugging information from exmh about which line[s]
	cause the problem

Thanks,

Mark