What?
So many people asking this when the solution is a bit of aesthetic styling. 
ol{margin:4px}

-- yields
995.
996.
997.
998.
999.
000.      <-- What's going on here then?
001.
002.
Or check out this screenshot of the issue:
Ordered List Issue

How?
The number just doesn't fit in the margin and needs more space. You need to increase the margin-left of the ordered list (ol) so for example, the fix in the above image was to set the margin-left to 10 pixels: 
ol{margin-left:10px}

-- yields
 995.
 996.
 997.
 998.
 999.
1000.
1001.
1002.



Other Searches
  • Ordered list gets reset to 0
  • numbered list > 1000
  • Ordered list resets to zero after the ninth item
  • Ordered List Maximum