question about a g-tube

I am a hospice nurse looking after an ALS patient. He recently had his mushroom style tube replaced with a balloon style g-tube. Everything was good for the first few days. When I visited today his wife said that over the last couple of days there has been increased pressure when she removes the tip to feed him. It is flushing fine and the feeding is going in without any problem. She said the pressure has gotten bad enough that it forced the feeding connector out while his feeding was going through the night. Any ideas on what might be causing this?