I don't know :-( I've tried to use the Trac site looking for particular changesets and found that for some of them, the list of files are out of sync with reality, and sometimes the diff don't have anything to do with what the commit message says.
cvs2svn will group multiple independent commit's together, I think if it sees commits within 300 seconds (should be adjustable) of each other it will group the comments all together. This may be the issue you are seeing.