Your approach isn't remeasured for where you are now
Speed and stride length change with training, fatigue, even the shoes you wear that day. If you're stepping over the board by a consistent foot or two, the mark you used last month doesn't match the jumper you are today. Re-mark stride one from your actual full-speed takeoff, not from memory, and confirm the mark holds for six of six reps before you trust it again in competition. This single fix resolves most chronic scratches, since a lot of jumpers are still running a mark set for an earlier, slower version of themselves.

