using NFS is an unsupported and dangerous setup: Disqualified for unknown reason - #19 by Alexey
This has been communicated multiple times.
So you can’t really blame storj for that…
You can read about a lot of DQed nodes using NFS: Topics tagged nfs
About the “empty folder problem” on connection loss:
There are several threads about using a subfolder in case the mountpoint vanishes so that the nodes fails. This is indeed an unpleasent problem and as of now there is no solution built into the software but it has been mentioned multiple times and we hope there will be a safety built in some day. Until then the recommendation is to use a subfolder.