LTC6811 Chinese fakes?

Its highly unlikely to have fakes. Can you please provide the details from where did you procure them? How are you testing them? What commands are you sending to confirm that they are not responding? Have you followed the recommended layout guidelines and referred the demo board schematic while using it in your hardware? 

The chips are being tested on custom hardware. In this hardware, the chips that are above in the photograph work perfectly, with all their functionalities. Measurement of tensions and balanced.
However, when soldering the chips below in the photograph, it does not even read voltages.

Can you please provide the vendor information from where you procured both of these parts? 

Can you share your HW schematic to just cross check all the design guidelines are being followed? 

In what test conditions are you running these tests? what is the V+ voltage forced? what is the SPI configuration? 

In how many boards are you seeing these parts not to work? 

As a basic check I can recommend you to do i send some SPI data to the IC, this will raise the DRIVE pin voltage to 5.7V. Can you please verify if you are getting this voltage? Please ensure that while doing so you are giving min V+ voltage of 12V/ 

Can you please provide the vendor information from where you procured both of these parts? 

Can you share your HW schematic to just cross check all the design guidelines are being followed? 

In what test conditions are you running these tests? what is the V+ voltage forced? what is the SPI configuration? 

In how many boards are you seeing these parts not to work? 

As a basic check I can recommend you to do i send some SPI data to the IC, this will raise the DRIVE pin voltage to 5.7V. Can you please verify if you are getting this voltage? Please ensure that while doing so you are giving min V+ voltage of 12V/