I keep having the same problems. I'm running 4.2.3 and the CS Cart Rock add-on.
The Catonical references are NOT working properly in Google.
The Multiple page category issue above: What seems to be happening is that the multiple page categories create urls, which are crawled and added. Then if we remove items and the page count is less then we get errors. The same happens with currency and languages. I've added a long list of URL parameters, but these don't help if the multiple pages are 404.
Individual products in multiple categories: I've gone back and forth with you now for several months; the crawl errors are continuing to be referenced as 404s, they are found as recently as a couple of days ago, after a new “Fetch as Google” was preformed (numerous times).
I'm running 4.2.3 and my products are generally listed in two categories; the shop store and manufacturer. Our packages that don't have two categories rank fine, near the top, the others in the two categories are buried - way back in the ranks. My Structured Data doesn't show well either. Duplicate content issues are the only answer; as everything else is the same.
I've talked to some SEO guys who've looked over the pages and they said they seem fine; heads, descriptions, etc. But I'm getting lost.
Something about CS Cart/and you catonical references just don't seem to be working with Google.
Am I the only one seeing this problem? If so, what is wrong? How do I fix it. My devs are shaking their heads.
In my opinion, the canonical url tag is the best way to solve it in case Google (or Bing) doesn't still indexed these links. However, in this case, coz' Google (or Bing) indexed them so you have to remove one url by disavowing it with Google (or Bing) in webmaster tool.