I am having a strange problem with my Magento installation. As soon as I add a product to my wishlist (any customer), I am getting the following error in the browser's console:
Item (Magento\Wishlist\Model\Item) with the same ID X already exists.
Due to which the mini cart is not showing cart items count.
I tried to truncate the tables related to wishlist:
But every time an item is added to the wishlist, the error appears in the console.
One more (maybe related) error I noticed is in customer-data.js
Maybe this is also a relevant clue:
Update: I have tried to disable the custom modules which are overriding customer-data.js.
Thanks for your kind help in advance.