I FINALLY FIGURED OUT!

you guessed it. ATLA THEORY TIME!!!!

Remember this scene?

Azula was able to trick Toph in this scene, and I think it's not because her heart is cold (wink at the antis and shows my middle finger) nor she has her breathing under control, nor because she is just this manipulative.

I think it's because of the addition of so much unnecessary and unknown information for Toph. She includes 3 colour names and her "height", wich I severely doubt it was even taught for Toph. Also, she was describing the shape on an animal differently of what it looks like, wich would have to include Toph's imagination for her to figure how the fuck it looked- wich is also a hint. Toph doesn't know how a platypus-bear looks like. She can tell its weight probably, and its general shape and form, but not how it looks.

Therefore, I think Toph was mostly stunned by the clear discrepancy of what she was sensing, what was being described and especially the riddled information.