The program has opened the standard labeled tape data set to read it forward but the volume that open has positioned the data set to is not the actual first volume of the data set. This message can also be issued during EOV concatenation processing.
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 637 rc B8 and message IEC026I.
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 standard header and trailer label 1, volume sequence fields are valid (example, incremented by 1 relative to the previous volume of the data set). Determine whether the data set serial number field in the first specified volume's label 1 should in fact contain that volume's serial number.