When using the build-in commit interface, it seems pre-commit is executed sometimes, post-commit never. I assume the configuration is ok as pre-commit gets executed (sometimes).
echo "pre-commit" >> /tmp/git_heartbeat
echo "post-commit" >> /tmp/git_heartbeat
git push origin master
echo "post-commit done" >> /tmp/git_heartbeat
The hooks have correct permissions and executing commit from the console fires both hooks.