OPNcentral NAT sync crash after upgrade to 26.4 (TypeError in BaseSection.php)

[ews]

Hello,

after upgrading OPNsense Business to 26.4 we are seeing OPNcentral sync failures on some firewalls during NAT synchronization.

Error:

TypeError: Cannot access offset of type string on string in /usr/local/opnsense/mvc/app/controllers/Deciso/OPNcentral/Api/Sync/BaseSection.php:162

Stack trace:

Deciso\OPNcentral\Api\Sync\BaseSection->array_iterator()
Deciso\OPNcentral\Api\Sync\Nat->extend()
Deciso\OPNcentral\Api\SyncController->reconfigureAction()

Observations:

only happens after upgrade to 26.4
issue seems related to NAT / Destination NAT migration
affected systems use multiple Destination NAT redirect rules
disabling NAT sync avoids the issue
not all firewalls are affected

It looks like one NAT-related config structure is returned as string instead of array and crashes array_iterator().

Has anybody seen similar behavior after migrating to 26.4?

Regards
Christian