Hello,
I need help figuring out why Related Lists on the Custom object shows no records.
We have a Custom Object named SDP, which has the following relationship. It is auto created via a Flow when certain criteria are met on Opportunity. Account, Opportunity and Contract fields are auto populated on the SDP record but in the Related Lists Section it shows zero records for these three objects.
Opportunity - Master-Detail(Opportunity) - SDP is Child object
Contract - Lookup(Contract)
Account - Lookup(Account)
Bradley Weller (Fast Slow Motion) 
Forum Ambassador
Okay, that makes sense for the current structure where you see SDP as a Related List on Account. But if an Account will never be a child of multiple SDP records, it's typically best not to create a lookup on Account to SDP. If you want to see details about the Account on the SDP page, rather than using a Related List, you could add a Related Record component to the Lightning Page.
https://help.salesforce.com/s/articleView?id=sf.lightning_page_components.htm&type=5
