DIAGNOSIS The robot's front bumper is getting pressed in by the rug fringe or pile when it tries to climb on, tricking the sensors into thinking it hit a wall.
FIX In the Roborock app, go to your robot's settings, find 'Carpet Settings' or 'Carpet Mode'. Turn ON 'Carpet Boost' and set it to 'Automatic' or 'Max'. This tells the robot to increase suction and adjust its driving logic when it detects a carpet, which often gives it the extra oomph to climb on without triggering the bumper.
IF THAT DIDN'T WORK For some rugs, the issue is the cloth anti-tangle side brushes. They can catch on loose loops. Try temporarily removing the side brushes and see if it navigates the rug. If it does, you might need to replace them with the stiffer, original side brushes.
HEADS UP If the rug is very soft or has a deep fringe, the robot might just struggle with it permanently. You can also create a No-Go Zone in the app to tell it to avoid that rug entirely.