Mine! I bet your poo was smooth in past two weeks.
For me, there was a lo hei with a lot of colorings; so I noticed my poo was suddenly ultra dark green one morning when i wiped with toilet paper.
The freshest salad I had from a lo hei was Haidilao's, the veges were freshly shredded. They made us wait quite long to serve the lo hei (before we started the main meal), they shredded the veges only when someone ordered the lo hei.