Sometimes you may notice frost/condensation on the back wall of your manual defrost fridge - please note this is completely normal and expected during regular operation.
The cooling panels for these fridges is along the back wall, so when in operation and the wall is cold, a thin layer of condensation may frost along the back wall, once the unit cycles and the cooling panels are turned off the frost will melt and water droplets will appear on the back wall. The water will then run down the back of the fridge and drain out into the evaporator tray located above the compressor where it will be evaporated.