Right before Pierre asks to use Katya's bathroom, she jumps onto her couch and then fixes her right shoulder strap on the top she is wearing. In the next few scenes, the strap alternates positions.
In the last scene, when the camera turns, Katya doesn't wear the cardigan she just had on.
At the beginning, as Pierre leaves the hospital to meet with Katya he calls a cab. His shirt is out and over his trousers. But at the hospital it is tucked in. And at the restaurant it is again tucked in. As Pierre leaves the loft his shirt is out of his pants as it it should be.
Katya's wireless microphone rig is clearly visible as a rectangular bulge just below the small of her back in several scenes soon after they go to her apartment.
It's clear that while Pierre is reading Katya 'her personal observations' re the darkness inside her, the cellphone is displaying only a blue screen.