The num parameter is a suggestion to Google, and in some cases, Google may not return the exact number of results specified in the num param.

The other possibility is some results were missing due to an issue in langchain.

I work for SerpApi so if you want us to look into what might have happened on the SerpApi side, please contact us through our live chat on https://serpapi.com/ or write to us at [email protected]

We'll be happy to help.