Why are there two Utsu-tsus?
In episode 4, it is revealed that Utsu-tsu has the ability to create copies of her body as one of her powers as a Gatchaman. It seems there are other modifications to her body as well, though these have not yet been completely explained. Her copying ability allows her to perform basic functions, but it seems that conversing and interacting with others is difficult through the copies. She uses this ability to simultaneously follow Hajime and O.D.

Here's a gif of her making a copy:



It's probably worth a mention that the opening theme actually foreshadowed this before the scene in the question: