The 4.14% is the correct figure. We tend to get upset as we tend to think simple expected probability accurately models RNG. This is only true if you take an infinitely large sample. For a small sample, simple expected probability is often not accurate. Based on simple expected probability (how are minds are rigged), you would get 2.56 rewards per day with a level 30 HC. However, there is in fact a 4.14% chance of not getting anything. That is a 1/24 chance. As a general rule of thumb, if an event has a greater than 1% chance of happening, don't get too agro about it. That will save you from a lot of emotional and mental distress.