Use the search function (magnify glass icon) and you’ll read previous threads on this subject as well as the problem you are experiencing. After reading those many message threads, you’ll find out that the temp sensor does not report accurately on a consistent basis when it is used outdoors.
Go ask yourself why do I have temp alert turned on for an outdoor camera in the first place? Cameras work just fine in very hot and very cold climates. This is way above and below the operating range specifications for the XT series cameras. Alarm for indoors make sense. Alarm for outdoor…who cares if the camera keeps working.
Turn off the alarm and carry on or have Blink replace the camera if you are in warranty time frame. Your choice.