FTP crawl does not use FTP's server root folder

Setup an FTP with root folder setup for a user (let's say test) pointing to /home/test/ftphome/

And create a folder under it called target with a test.txt file:
/home/test/ftphome/target/test.txt

Configure a URL to crawl as with depth of 1:
ftp://FTP_SERVER/target/

It will fail to crawl because the FTP plugin protocol assumes the path is always absolute. It will look into /target/ and not /home/test/ftphome/target/