GE Profile

Have a GE Profile refrigerator. Everything working OK except every couple days get about 1-1/2 cups water overflowing the drain line, shaped like the letter J, located next to the condenser coil at back of unit. Temperatures are OK, no water inside unit, no icing problems. Guessing water is from defrost cycle but seems like a lot. Is this an overflow drain? Should water being going somewhere else where it evaporates?