The correct answer to this open question is the following.
The statement, if true, that would explain the analysts' predictions would be "the Producer Price Index has been steadily increasing over the past few months."
That is what would have been the factor that supports the forecast. Although inflation has been constant at low levels, what changed was the Producer Price Index that is moving up. This factor could modify the results despite inflation is stable at this moment. When inflation is high, it directly affects the price of goods and the consumer.