Kerberos ticket not refreshed

Ever since upgrading to 11.3 my kerberos ticket would not get refreshed. So far I helped myself by manually creating a crontab which does a kinit every 6 hours.

Looking at it again I noticed an error during "/etc/ix.rc.d/ix-kinit renew":

freenas01# /etc/ix.rc.d/ix-kinit renew
'int' object is not subscriptable
Traceback (most recent call last):
File "/usr/local/lib/python3.7/site-packages/middlewared/main.py", line 130, in call_method
io_thread=False)
File "/usr/local/lib/python3.7/site-packages/middlewared/main.py", line 1084, in _call
return await methodobj(*args)
File "/usr/local/lib/python3.7/site-packages/middlewared/plugins/kerberos.py", line 365, in renew
tgt_info = await self._get_cached_klist()
File "/usr/local/lib/python3.7/site-packages/middlewared/plugins/kerberos.py", line 345, in _get_cached_klist
if ldap['kerberos_realm']['krb_realm'] in client:
TypeError: 'int' object is not subscriptable

The ticket itself FreeNAS got after bootup presumably via "ix-kinit start" (as this command works) seems fine:

freenas01# klist -v
Credentials cache: FILE:/tmp/krb5cc_0
Principal: host/freenas01.ipa.mydomain.com@IPA.MYDOMAIN.COM
Cache version: 4

Server: krbtgt/IPA.mydomain.com@IPA.MYDOMAIN.COM
Client: host/freenas01.ipa.mydomain.com@IPA.MYDOMAIN.COM
Ticket etype: aes256-cts-hmac-sha1-96, kvno 1
Ticket length: 384
Auth time: May 29 00:09:02 2020
End time: May 30 00:09:02 2020
Renew till: Jun 5 00:09:02 2020
Ticket flags: enc-pa-rep, pre-authent, initial, renewable, forwardable
Addresses: addressless

Server: ldap/ipa01.ipa.mydomain.com@IPA.MYDOMAIN.COM
Client: host/freenas01.ipa.mydomain.com@IPA.MYDOMAIN.COM
Ticket etype: aes256-cts-hmac-sha1-96, kvno 2
Ticket length: 388
Auth time: May 29 00:09:02 2020
Start time: May 29 00:09:05 2020
End time: May 30 00:09:02 2020
Ticket flags: enc-pa-rep, transited-policy-checked, pre-authent
Addresses: addressless

LDAP config:

freenas01# midclt call ldap.config
{
"id": 1,
"hostname": ["ipa01.ipa.mydomain.com"],
"basedn": "cn=compat,dc=ipa,dc=clouddrop,dc=de",
"binddn": "",
"bindpw": "test",
"anonbind": false,
"kerberos_realm": 1,
"kerberos_principal": "host/freenas01.ipa.mydomain.com@IPA.MYDOMAIN.COM",
"ssl": "ON",
"certificate": null,
"validate_certificates": false,
"disable_freenas_cache": false,
"timeout": 300,
"dns_timeout": 30,
"idmap_backend": "LDAP",
"has_samba_schema": false,
"auxiliary_parameters": "",
"schema": "RFC2307",
"enable": true,
"cert_name": null,
"uri_list": ["ldaps://ipa01.ipa.mydomain.com:636"]
}

Not sure if I read the code correctly but "_get_cached_klist" tries to check if ldap['kerberos_realm'] string appears in the "client" field of the LDAP config. But according to ldap.config "kerberos_realm" is just "1" (presumably the index of the defined realms?). Also is it trying to access a subkey with "ldap['kerberos_realm]['krb_realm']" ? krb_realm does not seem to exist neither in the top-level config nor as a subkey of kerberos_realm.
Could this be the reason why ticket renewals always fail on my machine?

Thank you for all your work.