Magento 2 Wrong Product Canonical Url
Unfortunately Magento 2 can add the wrong product canonical tag containing a 301 redirect URL. In the following file and method it can be fixed:
vendor/magento/module-catalog/Model/Product/Url.php::getUrl()
Add redirect_type code above the urlFinder code:
$filterData['redirect_type'] = 0 ;
$rewrite = $this->urlFinder->findOneByData($filterData);
It might be fixed in newer Magento 2 versions. This was discovered in version
2.3.6.