II have multiple websites and storeviews in my Magento 2.2.2 installation.
I have experienced a weird issue, that for some storeviews, when adding a product to the shopping cart for the first time, the mini cart is not updated, and still showing empty cart (see screenshot).
But when I add the product again, then Minicart is updated, but the Quantity besides the minicart is showing 1, even I can see both products - the previous one, and the new one.
I have tried the solution from this post Mini cart not show product when add product for first time Magento 2.1 but didn't help.
I'm using Magento 2.2.2