It is a normal Markdown behavior

The script sees something like a number followed by a dot, and it converts it into an ordered list, no matter what number you use

10000. Item 1
1. Item 2
9. Item 3
   1. Item 3a
   1. Item 3b

1. Item 1
2. Item 2
3. Item 3
   1. Item 3a
   2. Item 3b