No, it's not a confidence thing as far as I know. I was pretty involved in that huge bug thread about this particular problem, and it only happens to very fast WRs. The WR is too fast for the sims "ticks" which are like moments in time. For a WR to catch the ball, he has to make a "Can I catch it" check, then he'll attempt to the catch. What happens if you're too fast is the ball is thrown and the tick right before it gets to your WR, he makes the check, and the ball is too far. Then, in the very next tick, your WR is so fast that he actually outruns the ball ever so slightly to the point where when he makes the "Can I catch it" it is too far behind him to even attempt the catch.
So basically imagine the "ticks" as seconds or something, and actions can only be made on those ticks. Your WR is so fast that the ball never reaches your "can I catch this" radius. One tick before, the ball is too far behind, one tick later, you have already moved so far that you don't even attempt to make the catch.
It sounds pretty complicated, but that's how I understood it. If you want to read the thread, it's in the bugs forum "WR incompletion case study" or something like that.
