Paypal not marked confirmed after Joomla Update from 3.6.3 to 3.8.3

-- HikaShop version -- : 2.6.4
-- Joomla version -- : 3.8.3
-- PHP version -- : 5.6

Updated my Joomla from 3.6.3 to 3.8.3 a few weeks ago. Hikashop seemed to be fine on the frontend and backend (e.g., no php errors or obvious functionality differences from hikashop). However, after looking through our deposits, we noticed there have been over 50 paypal orders that we received payment from, but were never marked created in the order history. I checked the payment log and our paypal statement and nothing seemed out of place. Additionally, the customers never received the "status change" email showing that the payment had been received and order marked confirmed. What's even stranger is that some of the paypal orders were correctly processed and order marked "confirmed."

Any idea why the paypal plugin is sporadically missing some of the orders and not marking them confirmed? When an order stays as "created" in the order history, it usually means the payment was rejected or the customer aborted the payment midway through.

Any help would be greatly appreciated. I can give ftp or admin credentials if necessary.

The orders are not being marked confirmed after Paypal confirms payment. Shows payment received on PayPal's end but the orders in hika still show created.

Also, the emails are working fine (except for the status change email). The problem doesn't seem to be with email functionality but rather the communication between PayPal and Hikashop.

I successfully updated hikashop to the newest version (after lots of debugging with cart module). Took a while as I made a custom dropdown for 2.5. Had to undo all of that for the nice new cart module you guys made.

At any rate, updating seemed to fix all of my issues. The legacy mode is an excellent feature you guys added. Wouldn't have been possible to upgrade without them.