error 500 in API

If you use this API method:

https://api.envato.com/v1/discovery/search/search/item

if you use the pagination, the pages from 61 when page_size = 1000 have error:

{
“error”: 500,
“message”: “Invalid response from backend”
}

is the same from page 121 when page_size = 500 or starting at page 601 when page_size = 100