The headline is quite inaccurate. The processors are doing what they're designed to do; approximate the results of certain operations to a "good enough" value to achieve an optimal result:work ratio. Sort of like how the NFL measures first-downs with a stick, a chain, and some eyeballs rather than bringing in a research team armed with scanning electron microscopes to tell us how many Planck lengths short of the first down they were.
This is a documentation failure. They're fixing the documentation. For anyone who would actually care about perfect accuracy in these kinds of operations, there are any number of different solutions to achieve the desired, more accurate result. The headline and the summary make it seem as though there's a problem with the processor which is simply incorrect.