Yes, its normal.
The shelves temperature displayed is the inlet temperature of the heat transfer fluid (it may change as per the recipe programmed). The material trays temperature displayed are the raw products real-time temperatures.
The fluid provide energy to raw product, enable frozen water inside sublimate to vapor. When sublimation freeze drying starts, the temperature difference may 20C or higher, but as per the process goes and water removed step by step, the temperature difference will be smaller and smaller, when freeze drying finish, the temperature of them will be same!
