One of the reasons for this may of course be overheating of the extruder. It can also be caused by printing above the recommended temperature for that material. But this is not the case here since the print was fine up to the point where it started burning. Since the part is narrow on the top, there isn’t enough time for a layer to cool down before the next layer is extruded on top of it. To fix this, we can adjust the minimum layer time in the slicer. Furthermore, you can also check the ‘Lift head’ box which makes sure that the hot nozzle is not near the part while the extruder is waiting to reach the minimum layer time before moving on to the next layer
The minimum speed setting is also a crucial parameter here since it overrides the minimum layer time setting. Even when you set the minimum layer time, if the minimum speed is reached, the extruder will not go any slower. Keeping the minimum speed at 0 mm/s makes sure that the g-code always follows the minimum layer time setting.