PayPal Multi-Item Shipping Recalculates ONLY once Checkout or Login is Hit

[gruesome]

Problem:
Adding 2+ items to the cart - everything is added to the cart and calculated as expected.
Clicking Checkout (or login) - all of a sudden the total gets garbled and a completely unexpected amount is shown to the buyer.

The last several orders have come through with $0.00 shipping and this is happening once the buyer is on PayPal and not before.

Is there anything I can do to fix it?

I have checked the HTML variables and as far as I can tell, I am not missing anything!

Using Website Payments Standard / HTML buttons.

My site: http://www.gruesomeevolution.ca

[MTS_Ciaran]

I'll need some time to test this, I'll report back ASAP. 

[MTS_Ciaran · Accepted solution]

OK so, think I may found the issue, we had a bug recently which caused this, the fix for this delivered on Monday so issue should not be showing at the moment and based on my testing I wasnt able to reproduce. 

[gruesome]

Thanks for looking into it.  Did a test cart as well, appears to be calculating correctly now!