This question is the extension of THIS question. Posting again (with simplified code) as I am blocked in this issue.
Even for very simple form as below I am getting [object object] error.
<lightning:recordEditForm recordId="{!v.recordId}"
objectApiName="Opportunity">
<lightning:messages />
<lightning:outputField fieldName="Name" />
</lightning:recordEditForm>
This user has access to record, to field (editable ofcourse) and the field is on page layout.
Any other checks/directions would be appreciated. Thanks!