MP mp_payment_confirm acting weird

Quick breakdown of my setup.
Wordpress 3.3-beta3-19254 (Testing MarketPress Heavily In anticipation of the official release)
MarketPress 2.3.1
Paypal Express *Global Checkout*
Paypal Sandbox
No other known plugins are installed that tend to mess with a Marketpress installation such as Domain Mapping etc.

I'm having some issues during the final checkout step on both individual store checkouts and the global store checkout. Everything goes as planned up until my final confirmation page. Paypal creates and recieves the tokens correctly but after paypal processes the payment I get some weird problems.

On the front end it just dies on the /confirm-checkout/ AFTER I click to submit the final payment and does not redirect to 'confirmation'. If I refresh the page and resubmit the $_POST I get a whoops you skipped a step and my $global_cart is not unset and still displaying products. I also get the paypal error that says an order has already been completed with that token etc. I checked the wp_redirect and wp_safe_redirect functions in wp-includes.php/pluggables.php and found no changes. Plus wp_redirect is working in other locations. So obviously something in the do_action( 'mp_payment_confirm_'...) is killing the output before the wp_redirect and exit; statements. marketpress.php line 2706

On the admin side the order is created successfully even with different store items in the global cart which tells me no issues with switch_to_blog() which has given me trouble in the past. But interestingly the population of the order itself is messed up. The order has logged all the paypal information correctly. This includes the transaction ID the paypal payment amount etc, but certain marketpress variables are missing. The order is marked paid but without a timestamp. Cart Total is missing but the cart contents are correct.

Ok so now considering this is a crazy ridiculous problem that most likely I have created myself by meddling in the core (some very minor adjustments that were no issue in the past) I don't expect staff to "fix" this for me. ( thank god, right? ). What I would like some guidance on is what function or variable is handling the information that might cause an irregular error such as this to occur. My first inclination was something with the $_SESSION variable but everything looks fine when I print it to reference. My second hunch is that the oops you skipped a step message is not just a fluke. So could you tell me how marketpress decides if I have skipped a step (i thought it was the $_SESSION though?).

Your help would be much appreciated I imagine you will have to ask Aaron or someone to help with this.