While there can be lots of reasons to miss a huge target, and operator error ranks #1- please don't ask me either how I know- it is also more likely that your 4th ball went through a hole made by one of the first three. It happens more often than we like to think. Sometimes, a very close inspection of each of the remaining holes will show just the slightest hint that the hole is not truly as round as the others, indicating that a second ball went through the same hole, only not quite! If you are putting 3 shots that close, or closer, I would not spend a lot of time worrying about this.