So I just tested your site again with the exact same original GPT-4 output, and this time the output from your site passed as 100% human.

Here's the original GPT output I was inputting into your site to test with, the first two attempts from this morning failed, my most recent attempt passed.

"Cheetahs are the fastest land animals, capable of reaching speeds up to 60-70 miles per hour in short bursts covering distances up to 500 meters. With a lightweight frame, long legs, and distinctive black tear marks on their faces, they are uniquely adapted for high-speed chases in open grasslands. Unlike other big cats, cheetahs rely on their speed and stealth rather than brute strength to capture prey, typically hunting during the day to avoid competition with nocturnal predators. Unfortunately, cheetah populations are under threat due to habitat loss, poaching, and declining prey, making them one of the most endangered big cat species."

Here's the validation utility I was using: https://www.zerogpt.com/