I could be wrong but I believe a behavior has changed from jQuery 1.4.1 to 1.4.2

I have code similar to this:

if(typeof($('#someID').data('somekey')) == 'undefined'){

alert('1. NOT SET');

} else {

alert('2. IS SET');

}

In 1.4.1 (and previous) if the key wasn't set, the typeof test returned undefined (e.g. Alert #1)

In 1.4.2 I get into the else block, because the typeof is returning 'object'

Did I miss a key part of the 1.4.x upgrade notes? if it was changed on purpose, how does one tell if the "key" is not set yet?