I have seen the same with personal mail on LEPICS. My guess is that this
is a bug in EXECIO PUNCH, or quite possibly CARDPH: UR devices were fully
synchronous under SP, so that a SIO held the virtual machine until the
I/O completed, but they are more asynchronous under XA, and it becomes
important to wait for the CE before filling the buffer with the next
card. Try running LISTSERV under CMS 5.x.
Eric