Also you just said VPN next to captcha. It is common knowledge that using a VPN, you will have a shared IP with other users of said VPN. Commonly people run scripts against Google, to scrap intel, and or find victim results to attack; exploit to break in.
It is highly likely an evil human used the VPN to attempt Google dorks for malicious queries. Rather than complain about getting captchas while on VPN, go build your own VPN with your own unique IP address and you will rarely get captchas.