I saw this behaviour, when smb2 was enabled.
connecting over IP or another DNS name (like FQDN) gives a Kerberos host mismatch and falls back to NTLM authentication, which normally works.
maybe the home share mapped with AD tries Kerberos auth and the logon scripts do NTLM auth.
which Ontap version do you have? there have been some bugs with Kerberos token sizes. one is still open and will be fixed in 8.2.2, but on FAS2020 the latest you can go is afaik 7.3.7P4.