The numeric volume sequence value in the tape data set label is not as expected. The system expects it to be 1 greater than on the previously read volume when reading forward or 1 less when reading backward. The system does not expect each volume's label 1 to correspond to the number of the volume in the data set's volume list, but it expects the volume sequence number to be one greater than on the previous volume when the data set was being written. The difference between the expected and found volume sequence represents the number of volumes missing.
The system calls the label anomaly installation exit routine. The installation exit provided by IBM takes no action, and therefore the system ignores the condition. The label anomaly exit of your installation might cause the system to issue ABEND 413 rc 58 and message IEC145I.
This is either an error, an intentional action by the user, or the tapes are from another operating system. If you have a system automation product that can distinguish between a user error and the other causes, you may be able to configure that product to correct the error or to cancel or stop the job. DFSMSrmm can correct the volume list.
Possible error. Check whether the volumes on the DD statement or the dynamic allocation are complete and in the correct order. Check whether the numeric values in the volume sequence fields of the standard header and trailer label 1 are valid - example: incremented by 1 relative to the previous volume of the data set.