The sensor is located on the case (not near the exhaust) of the server. With the structure of my appartment this is the only place I can realistically put my Server but sadly also the hottest place in my appartment.
The outside temperature is supposed to reach 36°C today so I expect the ambient temp for the server to rise another 2-3 degrees.
Been happening to me as well. And my basement is more cool than my 1st and 2nd floor.