rsync --copy-unsafe-links problem with a relative symlink (does not copy) - copy

Question

When I use rsync with option --copy-unsafe-links it does not work when a symlink is relative. If a simlink is absolute it works as expected: copies content of the target instead of creating a broken symlink.
I have a dir structure in /tmp:
rsync-problem
├── dst
└── src
├── a
│ ├── a-file
│ ├── b-symlink -> ../b
│ └── c-symlink -> /tmp/rsync-problem/src/c
├── b
│ └── b-file
└── c
└── c-file
after running rsync:
rsync \
--copy-unsafe-links \
--links \
--recursive \
/tmp/rsync-problem/src/a \
/tmp/rsync-problem/dst
I get a broken relative symlink: b-symlink -> ../b in the rsync-problem/dst/a dir and a properly converted absolute symlink into a file rsync-problem/dst/a/c-symlink/c-file
rsync-problem
├── dst
│ └── a
│ ├── a-file
│ ├── b-symlink -> ../b
│ └── c-symlink
│ └── c-file
└── src
├── a
│ ├── a-file
│ ├── b-symlink -> ../b
│ └── c-symlink -> /tmp/rsync-problem/src/c
├── b
│ └── b-file
└── c
└── c-file
man of rsync for --copy-unsafe-links:
This tells rsync to copy the referent of symbolic links that point outside the copied tree. Absolute symlinks are also
treated like ordinary files, and so are any symlinks in the source
path itself when --relative is used. This option has no additional
effect if --copy-links was also specified.
Does not state that this option has no effect when a relative symlink is encountered.
and if I understand correctly
This tells rsync to copy the referent of symbolic links that point
outside the copied tree.
/tmp/rsync-problem/src/b
is outside the copied src tree:
/tmp/rsync-problem/src/a
what am I doing wrong and how to make rsync convert relative symlinks into files as it does with the absolute ones?
Script to replicate the issue:
#!/bin/sh
set -ue
mkdir -p /tmp/rsync-problem/dst
mkdir -p /tmp/rsync-problem/src/a
touch /tmp/rsync-problem/src/a/a-file
mkdir -p /tmp/rsync-problem/src/b
touch /tmp/rsync-problem/src/b/b-file
mkdir -p /tmp/rsync-problem/src/c
touch /tmp/rsync-problem/src/c/c-file
cd /tmp/rsync-problem/src/a
ln -sr ../b b-symlink
ln -s /tmp/rsync-problem/src/c /tmp/rsync-problem/src/a/c-symlink
rsync \
--copy-unsafe-links \
--links \
--recursive \
/tmp/rsync-problem/src/a \
/tmp/rsync-problem/dst