You can see another object in front of the “mobile phone”; the woman is holding two objects on her left hand.
Here’s the video cued to 18 minutes 16 seconds:
Four seconds later, you can see the same woman from behind at 18 minutes, 20 seconds:
If you watch these two sections in slow-motion (playback speed 0.25), you will see that it seems that she is just holding her glasses along with the glasses case.
Mystery solved.
