It's exactly correct on my system.

```
bash-3.2$ pwd
/usr/local/share/etherpad/etherpad-lite
bash-3.2$ rm src/static/custom/pad.css
bash-3.2$ ln -s node_modules/ep_oae/static/css/pad.css src/static/custom/pad.css
bash-3.2$ file src/static/custom/pad.css
src/static/custom/pad.css: broken symbolic link to node_modules/ep_oae/static/css/pad.css
bash-3.2$ rm src/static/custom/pad.css
bash-3.2$ ln -s ../../../node_modules/ep_oae/static/css/pad.css src/static/custom/pad.css
bash-3.2$ file src/static/custom/pad.css
src/static/custom/pad.css: ASCII c program text
bash-3.2$ diff src/static/custom/pad.css node_modules/ep_oae/static/css/pad.css 
bash-3.2$ 
```