Intermediate proof provides a recovery period so that the dough can become more flexible and pliable. After proving, the dough piece is usually larger in volume, the skin is firmer and the dough stretches easily.
Usually 5 - 15 minutes is needed to allow the dough to relax enough for final moulding. However intermediate proof time will vary for different types of dough.
The results of dough spending too long in Intermediate proof are seen here in the large holes in this cooked loaf.