Hello,
Welcome to Microsoft Q&A,
petstore3.swagger.io is an open-source repository https://github.com/swagger-api/swagger-petstore
And the issue is already reported https://github.com/swagger-api/swagger-petstore/issues/99.
You can use a petstore mock server yourself (e.g., using Docker). That gives you a more reliable API surface. Or use a stable alternative sample.
Please Upvote and accept the answer if it helps!!