The related lists for the Default view of a record are incorrect. Either some are missing or there are too many or there are none.
The request for Related List data specifies the view=default for the Default view, so if you have a view named "default" and it has a related list record for that table it will return that related list instead of the one for the OOB Default view.
Delete the view named 'default' view since it can cause issues with the OOB Default view.
Alternatively, if the custom view named 'default' is completely necessary you should be able to just remove the related list record for that table.
Steps to Solution:
- Navigate to System UI > Views
- Search name = default NOTE: This is not the OOB Default view which would have '(empty)' for the name.
- Go to the Related Lists related list and remove all records.