My suggestion is (still) that you throw the camera in the trash. Despite changing 'sensitivity', updating versions etc etc etc NOTHING resolves this issue. Not sure TP-Link knows how to "train" AI. I've changed the angle of the camera. Now it is a pretty useless piece of art. Good luck.

 I'm having same issues with my C120 and also my flowers become people and pets, it's driving me crazy! I bought this camera because reviews said it had great AI, but now I feel ripped off and unfortunatelyto late to return. How do I get this to realize these are flowers not people and pets. 

I mean, everything gets detected as a person every now and then, and more often than not, cats, cars, insects, snow, and rain are detected as human. I mean, I've been using this camera for close to a year, and it's been a massive disappointment. Now my audio doesn't work either. I've already invested in cameras from different brands, but I would like my current one to actually work as well.
 

That being said, yes, I have the same issue with my C500, but I won't bother reporting it. Something tells me that this is going to be an ongoing issue, and I'll probably have moved on before then.