Try to run zpool status -v NAS
to see a list what 120 files are corrupted. And your last scrub was over 4 months ago...way too long in my opinion. You might want to run them more regular like once per month. Then you got no parity, so in case the scrub finds corrupted files it can only complain that these files are damaged but it can't repair them. For that you would need some kind of pool laylout with parity like a raidz1/2/3, mirror or striped mirror.
How do you bring your disk into the VM? Keep in mind that you shouldn't use HW raid with ZFS.