In Floor Only mode, the cleaner is not actually trying to climb the wall. This behavior is usually caused by the shape of the pool bottom.
In pools with a bowl-shaped or sloped design, when the cleaner moves up the incline, it may interpret the surface as part of the floor rather than a wall. As a result, it continues moving forward before changing direction, which can look like it is attempting to climb.
This is normal behavior and does not affect performance. When wall cleaning mode is selected, the cleaner will still properly climb and clean the walls as expected.