It looks like this is an issue with how the keyup event is being bound.
You can add the tabindex
attribute to you modal to get around this issue:
tabindex="-1"
So your full code should look like this:
<a href="#my-modal" data-keyboard="true" data-toggle="modal">Open Modal</a>
<div class="modal fade hide" id='my-modal' tabindex='-1'>
<div class="modal-body">
<div>Test</div>
</div>
</div>
For more info you can view the discussion on this issue on github
(Updated link to new TWBS repository)