We have 3 hosts with vSphere 6.7 with many datastore mounted in NFS 4.1 and a FAS2750 with ONTAP 9.6. I have follow this guide https://www.netapp.com/us/media/tr-4597.pdf but in every ONTAP upgrade we have problems of virtual machines disconnecting. Datastores lose connection for a few seconds, and when they come back browsable the VMs are "disconnected", only solution is reboot the hosts.. has it ever happened to anyone? with NFS 3 it works perfectly!