First of all, you can observe the time and place where the other party puts the incense burner. If you rest at noon or at night, it shouldn't have much impact. But if it is during the day or when someone comes in and out of your house, you need to be careful not to trip over the other person's incense burner or encounter the first-class accident.
Secondly, we can speculate whether something bad has happened through some folk sayings. For example, some people think that having an incense burner at the door will provoke evil spirits, which will lead to poor health and poor fortune of family members. But these statements have no scientific basis and can only be used as a reference.
Finally, if you feel that the incense burner at the door has brought trouble to your life, you can consider negotiating with the other party to solve this matter. You can try to communicate, ask the other party to move or adjust the position of the incense burner, or ask the local mage to handle it.
In a word, we need to treat and deal with the incense burner at the door rationally, and don't be overly superstitious and worried.