Had my first encounter with this on GitHub this week. Saw an initial PR come in, left some comments, more commits came in, tried it out, looked deeper at the code and realized it was garbage. Asked how it was tested, got classic ai response, followed up with a question about how / why, thinking step leaked as a comment

Wasted my time, the account is running around doing this with dozens of rejected PRs across many varied projects.

If you're curious: https://github.com/google/adk-go/pull/306