Map labels are world-unique, not level-unique.

arthur@Chani:~/src/freedroid/map$ grep name=\" levels.dat | awk '{print $3}' |
sort | uniq -c | sort -n | grep -v "1 name"
      2 name="139"
      2 name="247"
      2 name="249"
      2 name="296"
      2 name="302"
      2 name="329"
      2 name="420"
      2 name="476"
      2 name="493"
      2 name="516"
      2 name="543"
      2 name="571"
      2 name="598"
      2 name="614"
      2 name="615"
      2 name="629"
      2 name="742"
      2 name="751"
      2 name="821"
      2 name="883"
      2 name="999"
      3 name="123"
      3 name="711"
      3 name="834"