Nowadays many car drivers resort to navigation apps to decide which route to take. To be efficient, these applications increasingly use real-time data rather than historical data. However, delay is unavoidable since data collection, communication, and processing are necessary before their usage in the App. For this purpose, we introduce a macroscopic dynamic traffic assignment model to describe the behaviour of drivers in choosing which route to follow to reach their destination. We assume that a part of the drivers follows the directions of a navigation App, whose directions are based on delayed traffic data. Through the stability analysis of the model, we show and quantify the excessive level of delay in traffic data that can be detrimental to the efficiency of the network by being responsible for the appearance of oscillating trajectories and unsatisfied demand.