Please override the file:
Magento/vendor/magento/module-review/Block/Product/View.php
Find:
public function getReviewsCollection()
{
if (null === $this->_reviewsCollection) {
$this->_reviewsCollection = $this->_reviewsColFactory->create()->addStoreFilter(
$this->_storeManager->getStore()->getId()
)->addStatusFilter(
\Magento\Review\Model\Review::STATUS_APPROVED
)->addEntityFilter(
'product',
$this->getProduct()->getId()
)->setDateOrder();
}
return $this->_reviewsCollection;
}
and replace it with:
public function getReviewsCollection()
{
if (null === $this->_reviewsCollection) {
$this->_reviewsCollection = $this->_reviewsColFactory->create()->addStoreFilter(
$this->_storeManager->getStore()->getId()
)->addStatusFilter(
\Magento\Review\Model\Review::STATUS_APPROVED
)->setDateOrder();
}
return $this->_reviewsCollection;
}
you can see that I removed addEntityFilter for productId which is use for the validation.
Let me know if you need any further help