Cart Issues - Disappearing Items

-- HikaShop version -- : 2.6.0
-- Joomla version -- : 3.5.4
-- Browser(s) name and version -- : Chrome

I had a customer a few days ago contact me saying he was having issues with the cart, so after some time, he cancelled the order & went elsewhere to buy his items. I reached out to him to ask what the problem was. Below are the responses I received from him, the initial contact to tell me he was having issues, then his response to me asking him what exactly happened...any help would be appreciated as I cannot replicate the issue...

Initial Contact Email...

Hello,

I made an order today, seemingly by accident. Please cancel it. The cart was giving me fits about putting everything I wanted into it, so I went elsewhere for my hobby purchases. I didn't think the order was completed until I saw the confirmation e-mail.

His response to me when I asked what happened...

Hello,

I was using Internet Explorer and Firefox. I thought it might have been an issue with my Firefox so that's why I went to Internet Explorer. But it continued to do basically the same thing.

I was trying to buy 6 different items. That would be the imp, king crab, Devastator, Chevallier, the Galleon tank. I would add these items, and then try to view my shopping cart when I was done. For some reason, items would disappear, and then reappear. It seemed to me that the imp was the item causing the issue. Because I would add it, and if it would appear other things would disappear, or It would never appear at all.

After about 30 minutes, and two different browsers I just said forget it and I went with eBay. I was shopping here due to the recommendation of a friend.

Thank you for the considerate response.

As a side note, I also had a customer using Firefox who could not get to the site, they switched to Internet Explorer & everything worked fine.

Is there possibly an issue with some browsers? I personally test with Chrome, IE 11, and Edge, and never have problems myself.

Thank you

Thank you Nicolas. I believe there is caching enabled on the host side, but I will have to double check. Since I can't replicate the issue, I may have to hopefully work with the guy that sent me those to see if he continues to have it. I appreciate the tip!

Thank you & have a Merry Christmas!