For floor with soft wood, it maybe damaged by the obstacles like hard dust, ceramic, glass fragment sticked on the RS2 mop assembly and main brush, which belongs to a common phenomenon for RS2; influenced by the color, RS2 may not effectively detect and avoid the skirting line if the skirting line is made of dark light-absorbing material or with partial embossing, so that there is a certain probability that it will trigger a slight bump, which may cause scratches over time.