Sometimes ....
... despite pre assess and careful planning using the Progress on Topic the teacher will realise that they have taught the learner something which is taking too much feedback and practice time and the learner doesn't look like they will master that piece of learning soon, the teacher should assess the layer best learned later (the bell symbol).
The teacher should be pleased with themselves for doing excellent assessment for learning and recognising this.
The teacher can app will remove the layer from the retrieval practice cycle by deciding the layer is best learned later. Without timely practice the best learned later layer would have been quickly forgotten. The teacher should decide that this layer will be removed from the learners' timely practice pool (all the layers the learning is practising) for now, so that the learner can concentrate their efforts on all the other layers. When the teacher thinks the learner is ready the teacher can teach the learner the layer again.
Remember ...
... without timely practice this layer, and many many other layers, would have been very quickly forgotten - the timely practice app is designed to save as many as possible from forgetting - but sometimes the teacher and learner's efforts are best used elsewhere. There are plenty of other layers which the teacher and learner can concentrate their efforts on - which will pay greater dividends in increased learning. Provide the teacher and learner concentrate on these, at some time in the future these other layers will provide sufficient firm foundations for learning and increased motivation so that the teacher can teacher this layer later with far less effort and feedback sessions.