I am not sure why this happened, but one likely possibility is that there
is a very small amount of people using one of the two types of headers
you mentioned (most subscribers usually get short headers). While going
through the DISTRIBUTE process, LISTSERV@AKRONVM might realize that you
are the only recipient down the path and mail directly to you, ie through
its local mailer, to save cycles and bandwidth. With the other type of
header there might be 10 other people down that path and the DISTRIBUTE
process will continue normally.
Eric