Revert "accept the change from a number to null in TimePeriod fields #5319"
This reverts commit a3960fa7c279f2aa9fafbefde098c529e269d382.
Revert "accept the change from a number to null in TimePeriod fields #5319"
This reverts commit a3960fa7c279f2aa9fafbefde098c529e269d382.