ClassCastException on new Model after update running system on cluster

Hi,

I have defined a new type in items.xml (SalesOfficeWarehouseConfig) and created a relation of this type with an existing type (B2BUnit). On our single-node environments everything went fine after an update running system. But on the clustered environments, after the update running system we were left with ClassCastExceptions, which did not go away until a new server restart.

The method where the exception was thrown from is B2BUnitModel.getWarehouseConfigs:

java.lang.ClassCastException: de.hybris.platform.core.model.ItemModel cannot be cast to eu.shimano.b2b.hybris.core.model.SalesOfficeWarehouseConfigModel

Anyone has seen these exceptions as well, and/or knows how to prevent them?