TaxCloud errors after Order Canceled & Restarted

-- url of the page with the problem -- : new.littleapplewoodenpuzzles.com
-- HikaShop version -- : 2.3.1
-- Joomla version -- : 3.3.0
-- PHP version -- : 5.4.7
-- Browser(s) name and version -- : any
-- Error-message(debug-mod must be tuned on) -- : TaxCloud error : CustomerID is missing

I've known about this for a while and found this to be a minor annoyance for testers but I had a client complain about it now.

1) Using PayPal (standard) payment & TaxCloud with guest only checkout.
2) Tax eligible shipping address (has to be in Kansas) is used.
3) Customer clicks checkout button to go to PayPal.com payment page.
4) Customer clicks "Cancel and return to website" link from PayPal.com payment page.
5) Customer returns to "Empty Cart" message (as intended - Clean cart when order is set to "created").
6) Customer immediately starts another order.
7) Customer receives the "TaxCloud error : CustomerID is missing" error upon adding any taxable product to cart (see attached).
This error appears on any HikaShop generated page on the site, not just the checkout/cart.
9) Can only get ride of it once you enter a shipping address in checkout or close your browser (clear all session cookies?) and start over.

Unfortunately I cannot verify this on my eternal server as it is behind a firewall.

It looks one of the TaxCloud values are not completely cleared when an cart is cleaned. If I go into the database via phpMyAdmin and clear the session record for that browser, the error goes away but the cart products stay in tact.

Any help would be appreciated to make the client happy.

EDIT for Additional notes:
1a) This also occurs after you complete an order successfully too. E.g. You click "return to website" from PayPal.com thank you page.
2b) This also happens when you use the HikaShop credit card payment plugin (after an order is completed and you immediately start another). I confirmed this one on my test server and the client's site.

I DID confirm that this does happen even when using the

Hello,
Can you show me through some screenshots how did you configured the "Hikashop TaxCloud Plugin" ?

This is the same site from my other thread regarding characteristics (nothing has changed):

My test server uses a different TaxCloud account / address but other wise identical setup in HikaShop.

Also keep in mind that TaxCloud itself is working fine with an actual order.
Correct rates, reporting back to taxcloud.net, etc.

It is AFTER an order is placed or canceled when the cart is supposed to be cleaned out.