Why does water occasionally leak from bottom of

I have a GE Profile side-by-side refrigerator that is about 10yrs old. Model is TFX25PRY. It is not hooked up to water for the ice/water in the door. It is in the basement so it gets light use. Occasionally it will leak water from somewhere that comes out of the bottom on the freezer side & drip on the floor. The amount is significant enough to get the wood in the wall next to the fridge wet. I was thinking it may defrosting or humidity related but don't think they would design it to drip on the floor so wondering if there should be some type of catch pan?