Redirects on product pages, Shopify?

Question

Online shopping

Good afternoon.
Found a problem on my website https://rometechcases.com/ . Some product pages redirect from the product page to a page with the same product, but with a different URL, which has the text “?variant= and a set of numbers” added to it.
Example:
Product page: https://rometechcases.com/collections/pixel-4a/pro... Trying
to go to this page redirects to the page: https://rometechcases.com/collections/pixel-4a/pro. ..
Such a problem with many products on the site, but not with all. Why did this happen? How can I fix this problem?