on an opportunity, we have a lookup field to the custom object(customobject__c) and we need to update the custom field(Text__c) of customobject__c based on the opportunity status field.
Note: On opportunity, we have a lookup field to the customobject__c and On customobject__c, we have opportunity related list where we can have many opportunities associated with the 1 customobject__c record

I created Three Custom Objects.
1. Custom Product
2. Custom Asset
3 Work Order
On all the objects there is custom field, named Description.
And Custon Product have self Lookup. Custom Asset is a child of Custom Product(Lookup relationship). Work Order is Child of Custom asset(lookup relationship).
If I insert Work Order and Select the Asset record then the value of Description is populate while insert if the selected asset record description field is empty then it populates the value of description of custom product of selected asset and if that is also empty then it populates the value of self parent of custom product of selected asset. 

on an opportunity, we have a lookup field to the custom object(customobject__c) and we need to update the custom field(Text__c) of customobject__c based on the opportunity status field.
Note: On opportunity, we have a lookup field to the customobject__c and On customobject__c, we have opportunity related list where we can have many opportunities associated with the 1 customobject__c record

<lightning:input aura:id="startDate" type="date" name="startDate" label="Date" messageWhenValueMissing="You must specify Date" required="true" />

But it always showing message ="Complete this field." And If I change type="text" it works perfectly.