An updated estimate can be part of a programme responding to the load. Cancelling whenever it changes can prevent the machine from reaching its intended finish.
Understanding this situation
This differs from a cycle that repeatedly fails to progress, produces a warning or overheats. The correct response depends on the model's documented behaviour and whether the load is suitable, not just a changing number.
A useful next step
Allow a safe normal programme to complete as instructed. Record persistent unexplained extensions with the load and target. If a safety symptom appears, stop appropriately; do not continue simply because changing times can sometimes be normal.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.