I have some balls that do this quite often. They are typically spider morphs though :-o. The rest of my collection strikes and eats fine for the most part.

It could be that the feeder is not warm enough which can cause them to pick up more of your heat signature rather than their food's. I try to heat mine up to the point where they are nice and warm to the touch (~90-95°). Not only do I get a great feeding response from this but they are less likely to miss :-).

Good luck. I hope this reassures you.