If you have set up AMP to go to your normal website after clicking on the "Next page" button, you need to make sure that the number of products/blogs on your AMP page matches the number of products/blogs on your non-AMP page.
Collection/Blog Page pagination
If you are on your AMP page at mysite.com/a/s/collections?page=1 and you have set up AMP to go to your normal website after clicking "next page", then you will always go to your normal page: mysite.com/collections?page=2. This is perfect, and it is what you would expect, but if your normal site has 40 products (or blogs) per page, and your AMP site only has 10 products (or blogs) per page, you can see where this would go wrong. It would mean that the user sees 10 products, numbered 1 through 10 on the AMP page=1. But when they click "Next page", they will see 40 products, numbered 41 through 80, on the non-AMP page=2.
To fix this, make sure that the number of products on your AMP website matches up with the number of products on your non-AMP website. You can adjust this setting using the AMP theme customizer. Follow these steps:
Navigate to your AMP themes dashboard here.
Open the AMP theme customizer by clicking on the blue "CUSTOMIZE" button next to your desired theme
Select "Collection pages" from the top drop down
Adjust your settings on the left from which you will be able to choose the number of products on each collection page. The format is different for each theme, but each Collection Page has a section where this is adjustable on the left. For example, here is the setting on the Debut AMP theme:
Once the number of products on your AMP collection pages matches the number of products on your non-AMP collection pages, (for example, if you have 40 products), then the user will see 40 products numbered 1-40 on AMP, and then when they leave AMP to go to page 2, they will see 40 products again, numbered 41 through 80. If you don't have a page 2, then this will also operate properly, because the system will paginate to make up for that.