Why are some data not visible after migrating from version 3.x to 4.x?

Add-on:Scaffolding
Question:Why are some data not visible after migrating from version 3.x to 4.x?
Answer:

This may be a rare case where ContentID is not converted properly. Please check if this the case by viewing the error logs and see if the error displayed is similar to this incident: Migration Problem. Once this is confirmed, follow the steps therein to display pages whose values are not shown.

We will look into fixing this in future releases, e.g. post Scaffolding 4.0.3.