In my experience, some frogs prolapse for a couple of reasons as well as parsite realated issues.. 1 being how clean is the cage,2 being the cricket is to large for the animal (in which the space between the frogs eyes should determine the size of the cricket), 3 temps are to low and the animal cannot digest it (mid 70's during the day is perfect), 3 too much calcium carbonate can cause intestinal blockage..
Just a thought and hopefully something helps you out..