Regardless of the technical details, I believe the author of the article is making the wrong assumptions.
He is talking about errors depending on the internal state of FPGA, or "the guy operating the device leaving the door open" leading to a change in temperature (very unlikely, but still you have to consider everything).
The problem is that all of these possibilities would lead to different readings on multiple trials, while we are not talking about a "one off" experiment, but one that has been tried several number of times and the result has been consistent.
An error might still be there, but clearly is not based on a random internal state or outside conditions, but must be systematic.
He is talking about errors depending on the internal state of FPGA, or "the guy operating the device leaving the door open" leading to a change in temperature (very unlikely, but still you have to consider everything).
The problem is that all of these possibilities would lead to different readings on multiple trials, while we are not talking about a "one off" experiment, but one that has been tried several number of times and the result has been consistent.
An error might still be there, but clearly is not based on a random internal state or outside conditions, but must be systematic.