I cant reproduce this using 6.16 on Win2ks.
I wounder if these files were being downloaded from a xdcc bot using klipper, I know that script has a fault in it, that they dont seem willing to acknowledge or fix.
If it is you can go into xdccklipper.mrc search for .timer 1 0 close -g $nick and remark the line.
Its in this routine.
on *:FILERCVD:*: {
... stuff here ...
.timer 1 0 close -g $nick
.... stuff here ...