DIAGNOSIS: The robot's bumper is making contact, but its upward-facing infrared sensor on top is not detecting the overhang soon enough. This is a design limitation.
FIX: You must create a Keep Out Zone in the iRobot HOME app. After creating a Smart Map, edit the map and draw a Keep Out Zone over the problematic cabinet overhang or chair legs. The robot will not enter that area on future jobs.
IF THAT DIDN'T WORK: The bumper sensor might be dirty. Clean the thin horizontal infrared window on the top front edge of the robot with a dry cloth. Also clean the bumper's front surface so it can depress fully on contact.
HEADS UP: The m6 does not have the same advanced cliff and obstacle detection as a Roomba. It is designed for open floors. Always do a pre-clean walk-through to remove chair rungs and low-hanging tablecloths.