I have a Liebherr fridge (KSves 3660 Index 27/147) which is 5 years old. It has been working fine, but we’ve noticed some water on the floor. We pulled it out to take a look and the tray which collect defrost water is full. There is also some strange, clear sticky gunk in the tray which has also dripped onto the floor. Any ideas or should we just clean it up and ignore it?