Open Cart - Very bad SEO behaviour. bug?

Let's say we have 10 categories with 10 products each. Then this should be around 100 links.
Two exampels:
Category: processors
Product: amd-zyren-1700
Link: shop.com/processors/amd-zyren-1700

Category: graphiccards
Product: readeonXXL
Link: shop.com/graphiccards/readeonXXL

So far, so good. But I realized with an audit from website auditor that there are many 301 redirects.
So, not only does this link exits:
shop.com/graphiccards/readeonXXL

But also this one with a redirect:
shop.com/processors/readeonXXL

So, with a shop that has 10 categories and 10 products, this gives about 900 (!!!) unnecessary redirects.
I DO NOT WANT THIS. This can not be good.

How to stop this behavior? A link with a product and a random category should simply not exists. I don't see any need for this!

Fix? Please?

What version of OpenCart are you using? Are you using an extension that is adding the 301 redirects? As there are not 301 redirects for products or categories in OpenCart.

I use 2.3.0.2
I am using several plug-ins, including the mega header menu for navigation.

It is totally unclear to me what is causing this 301 redirect.

Try disabling the extensions one by one until you find the one adding 301 redirects. Also check your htaccess for any reditects other than the default ones.