I don't know what to say.
Global configuration cache, disabled. System cache, of course, disabled. If a third party extension use cache, I must find how to find it. Maybe it is hikashop
However, I installed cache cleaner pro, so a professional edition. It should do the job. Now, in fact it has not much effect. On save and apply, it must clean cache. I set it to give a message when cleaning (now I disabled the message), and it says it does. Useless. If I put in basket 2 items, is ok. The third, fourth, fifth, and (randomly) other, don't update the cart. At a (random) point, the cart is updated.
After in the proces of adding items, evenif the cart it is not updated, I jump to another page (Home, let say), then the cart it is updated. Maybe cache cleaner pro is doing the job corectly only at the page change (not update), or maybe it is not from the site, but from the browser (any browser, all do the same, and this make me to ask questions).
So, any ideea? Free acces at backend and popcorn...