As we have learnt, green lumber has a higher moisture content when it is used. This means that it will continue to dry out and shrink. What problems arise from the wood shrinking? One issue that can occur is that as the wood frame shrinks, it creates a gap between drywall and nails. As the two are pushed together, it can cause the nail to push out the drywall. Although no structural problems should result from this, it can look rather unattractive. Other gaps can be created from the wood shrinking as well.
Another problem is mold. If the wood is not properly dried out, it can cause mold spores to develop. Mold can have already developed even before the wood has been used.
Liquids such as sap gradually seep out of the wood, which will create discoloration. Water will still be evaporating out of the wood, so if the wood has been painted, it could hinder the evaporation process which will cause the paints surface to bubble and be unsightly.
As we can gather from this brief discussion, while not as expensive as dried out wood, green lumber can create a number of issues after construction.