This latter factor indeed comes very close to a New Keynesian type interpretation of the higher sensitivity of inflation to the underlying economic conditions, where different degrees of strategic complementarities in price setting can indeed be viewed as influencing the coefficient attached to slack (or, rather, the marginal cost of production) in the Phillips curve condition.
Market expectations for the likeliest terminal date of the APP have not coincided with the “expiry date” communicated in the most recent programme recalibration, but have instead typically extended beyond this expiry date. In other words: in forming their predictions about the most likely date for purchases to end, markets have not just looked at the date-based element of our guidance.