.Objects, .Clients and .Accounts is a Page Lists, and it refers to a Data Pages like D_Objects, D_Clients, D_Accounts.
And I have an exception on Property-Remove step with this text: Caused by: com.pega.pegarules.pub.PRRuntimeException: exception caught during invocation of PRObjectWrapperExtended.prRemove() for Property . Message: The reference D_Objects_pa7456981238521979pz.pxResults(3).Clients(1) is not valid. Reason: Cannot modify value of Reference Property without first linking it to another property using Property-Ref
This exception occurred for the first time. If someone faced this problem - please write how you solved it.