Parameter "pages" sometimes is not honored

[wang27jing]

Using the playground to test use. I have the following request. It is clear that this ASIN has a lot of reviews (actually ~190 reviews as I tested). I have received 8 reviews/page * 10 pages = ~80 reviews. Any reason the scraping stopped early at page 10 when "pages" is explicitly set to 20?
Result is attached: data.json

payload = {
'source': 'amazon_reviews',
'query': 'B0BPN4NL4R',
'parse': True,
'domain': 'com',
'pages': '20',
'start_page': '1'
}

response = requests.request(
'POST',
'https://realtime.oxylabs.io/v1/queries',
auth=('YOUR_USERNAME', 'YOUR_PASSWORD'), #Your credentials go here
json=payload,
)