I have been seeing sometihng strange in some of our clusters ever since we moved into the OnTap 9.x versions.
From a Windows 8+ or Server 2012+ machine, we are no longer able to navigate to the .snapshot directory in Windows explorer.
If you do a DIR in command prompt, you can see all the sansphots as you should, and the Properties -> Previous Versions tab also works as expected.
Something I have seen is that in if you navigate to the full path in Windows Explorer (such as \\nas.domain.name\share_path\.snapshot\daily.2018-03-02_0010) you can access it. You are then able to access \\nas.domain.name\share_path\.snapshot just like normal until you close out.
\\nas.domain.name\share_path\.snapshot - DOES NOT WORK
\\nas.domain.name\share_path\.snapshot\snapshot_name - DOES WORK
DIR \\nas.domain.name\share_path\.snapshot - DOES WORK
DIR \\nas.domain.name\share_path\.snapshot\snapshot_name - DOES WORK
Snapshots are set to visible for all shares.