starruby:
Well, when I disable SSU, then this problem does not occur. So it's confirmed that SSU is causing this problem. Is anyone else facing the same problem?
Regarding the shopping cart being empty after clicking "add to cart" - has this issue ever been completely troubleshot/resolved?
We have had this exact same scenario happen. When the SSU cache is refreshed, the problem goes away - but it returns anywhere from several hours later, to a couple of days later. In our case, it doesn't have anything to do with "www" vs no "www" in the URL. And in our case, the shopping cart will be empty with the same product repeatedly, until the cache is refreshed.
We refresh the cache after adding/editing products through Easy Populate. It happens regardless.