When deploying new dll's to the testservers the reflection mechanism re-registers the property types including EPiServers own contained in the Episerver.dll. When we deploy we first remove all old files andreplace them with new from our dev. environment. In the database (table tblPageDefinitionType) the newly registered property types recieve a new pkID (counter) but the TypeName and AssemblyName are still the same, this must mean that there must be something wrong with the reflection implementation.