This is what happens when I try to merge updates from trunk (up to r32172, just because I don't want to get too many updates all at once).

PROBLEM: it merges into www/svn_1.5_releasenotes twice, causing a conflict on the second time. It doesn't appear to be saying it's merging two different revision ranges.

In the following, I've only elided (with "[...]") lists of files being processed; I haven't elided any revision range notification messages ("--- Merging ...").

julianfoad@edith ~/src/subversion-branches/tree-conflicts
$ svn merge $SVN_REPOS/trunk@32172
--- Merging r31498 through r31715 into 'notes/tree-conflicts/design-overview.txt':
 G   notes/tree-conflicts/design-overview.txt
--- Merging r31498 through r31715 into 'notes/tree-conflicts/requirements.txt':
 G   notes/tree-conflicts/requirements.txt
--- Merging r31823 through r32172 into '.':
U    notes/tree-conflicts/resolution.txt
U    subversion/include/private/svn_mergeinfo_private.h
U    subversion/include/svn_error_codes.h
U    subversion/include/svn_dav.h
[...]
--- Merging r31498 through r31715 into 'subversion/libsvn_auth_kwallet/kwallet.cpp':
 G   subversion/libsvn_auth_kwallet/kwallet.cpp
--- Merging r31823 through r32172 into '.':
U    subversion/libsvn_ra/compat.c
U    subversion/libsvn_ra/ra_loader.c
U    subversion/mod_authz_svn/mod_authz_svn.c
U    subversion/libsvn_fs/fs-loader.c
U    subversion/libsvn_subr/config_file.c
U    subversion/libsvn_subr/config.c
U    subversion/libsvn_subr/cache-inprocess.c
[...]
U    subversion/libsvn_fs_fs/tree.c
U    subversion/libsvn_fs_fs/fs_fs.c
U    subversion/libsvn_fs_fs/lock.c
--- Merging r31228 through r31715 into 'tools/server-side/svn_server_log_parse.py':
 G   tools/server-side/svn_server_log_parse.py
--- Merging r31228 through r31715 into 'tools/server-side/test_svn_server_log_parse.py':
 G   tools/server-side/test_svn_server_log_parse.py
--- Merging r31823 through r32172 into '.':
U    tools/server-side/svn-populate-node-origins-index.c
A    tools/dist/getsigs.pl
U    tools/dist/post-to-tigris.py
A    tools/hook-scripts/commit-email.pl.in
 U   tools/hook-scripts
U    Makefile.in
U    www/links.html
U    www/getting.html
U    www/faq.html
U    www/project_status.html
U    www/tools_contrib.html
U    www/svn_1.5_releasenotes.html
[...
 ...  *** look: here's the first time ***
 ...]
U    contrib/server-side/svnstsw/src/main.c
U    contrib/server-side/svnstsw/src/fso_is_changeable.c
U    configure.ac
U    COPYING
U    CHANGES
--- Merging r31823 through r32172 into '.':
G    Makefile.in
U    build.conf
U    www/mailing-lists.html
U    www/release-history.html
G    www/links.html
--- Merging r31823 through r32172 into 'www/development.html':
 G   www/development.html
--- Merging r31823 through r32172 into '.':
U    www/project_tools.html
U    www/merge-tracking/design.html
G    www/getting.html
U    www/images/svn-dav-securityspace-survey.png
G    www/faq.html
G    www/project_status.html
--- Merging r31823 through r32172 into 'www/issue-tracker.html':
 G   www/issue-tracker.html
--- Merging r31823 through r32172 into '.':
U    www/roadmap.html
--- Merging r31823 through r32172 into 'www/tasks.html':
 G   www/tasks.html
--- Merging r31823 through r32172 into '.':
U    www/svn-dav-securityspace-survey.html
A    www/faq.ja.html
Conflict discovered in 'www/svn_1.5_releasenotes.html'.
Select: (p) postpone, (df) diff-full, (e) edit,
        (h) help for more options:

[...  *** and there's the second time ***  ...]