Why is current different in 2 identical parallel branches of my circuit?
There are specifications on how much your sensors can vary.  They are clearly not identical, and one of them is stealing current from the other.  Just look at the tables in section 6 of the datasheet you link to, and now think about what happens when one sensor has a minimum value and one has a maximum value.

This is the same for many different circuit elements, and is why things like LED's each need their own current limiting resistor when arranged in parallel. As Matt points out below, every time you parallel diodes and transistors you need to be aware of this.