Thanks for the update. Yes, it could well be.
I think looking at the version of the SnapCenter, you should be able to raise a ticket with NetApp. Have you already raised one regarding this issue ? If not, I suggest please do so, chances are your issue will get resolved sooner.
Also, I come across this KB, talking about DNS issue. I guess you have acces to KBs. Please take a look.
SnapCenter Resource "Availability Group":
https://kb.netapp.com/app/answers/answer_view/a_id/1087384/loc/en_US
Thanks!