Some workarounds:

1) use a ` ` to "break out" of the list prior to the code block:

eg.

* Item 1
* Item 2

 

~~~~
Some code
  code
~~~~

----

2) Indent by 4 spaces to make the code block a part of the list item:

eg.

* Item 1
* Item 2

    ~~~~
    Some code
      code
    ~~~~

And, since it's difficult to show the "raw" formatting, I've attached
the contents of this post to this ticket as a txt file.