Hmm, good question. According to this message there should be a file on the site for manual installation: QNAP security advisory for Roon Server - #48 by crieke
And yes that 16mb is something to worry about. Check your SSD/HDD configuration on QNAP settings. Also make sure that Roon actually installs on the correct location.
I thought that since Roon released new version today it might have automatically update on your QNAP and maybe it had something to do with this because QNAP has removed Roon app from their official appstore due the security breach. I’m home in two hours so I have to try if mine still works 