The typical order number looks like this: 000123-005. Internally it's being stored in 2 database columns.
|Database Column||Example Value||Padding Setting||Padded Example Value|
Both number are left padded with 0 to have similar width. Unfortunately the MySQL's LPAD function, used to do that has documented side effect: if a padded number is longer, then padded length, then number is being cut off. This way 123 turns out into 12 (3 is cut off), when somebody sets padding from 6 to 2 symbols.