Being charged for unused Amazon Virtual Private Cloud Public IPv4 Addresses in Free Tier

Hello.

Are you using any public IPv4 addresses other than EC2?
You can find the public IPv4 address in your AWS account using the method described in the following document.
https://aws.amazon.com/jp/blogs/aws/new-aws-public-ipv4-address-charge-public-ip-insights/

I think the following documents will also be helpful.
https://repost.aws/articles/ARknH_OR0cTvqoTfJrVGaB8A/why-am-i-seeing-charges-for-public-ipv4-addresses-when-i-am-under-the-aws-free-tier

Your screenshot is not showing the entire description. I suspect the first line with 30.649 hours is for free tier used by EC2 instances with public IPv4 address; whereas the second line is for public IPv4 address used by other non-ec2 service (NAT Gateway, Load Balancer, etc) which are not included by free tier.