Here we see an illustration of my earlier point about over generalizing from limited information. Last time he had trouble with your jab, this time he didn't. This could be for a variety of reasons. Maybe he was holding back last time or working on something specific that didn't function well against your jab or he was having a bad day or maybe you genuinely did a good job and took him out of his game. This time he adapted to what you were doing and showed you that the jab isn't some sort of a magic weakness for kickboxers any more than the roundhouse kicks you were having trouble defending against are any sort of special weakness for TKD practitioners.