On *:join:#:{
  Set %nick $Nick
  Timer.voice 1 1 goto voice
  :voice
  If (%Nick isreg $chan) {
    Mode $chan +v %nick
  }
}

    ^ should work if not,

on *:join:#:{
  /set %nick $Nick
  /timer.voice 1 1 /inc %time 1
  if ((%nick isreg $chan) && (%time => 1) && (%nick ison $chan)) {
    /mode $chan +v $nick
  }
}

on *:voice:#:{ if (($vnick isop $chan) || ($vnick ishop $chan)) { mode $chan -v $vnick } }


   ^ put the on voice on both, just as a safe guard, then try both joins