There may be a few issues, all of which are common with rep watches (especially kit watches). 1st, it looks like the printing on the minute subdial is slightly askew. If you draw a line along the bottom of the 20 & 10, the 10 appears to be slightly lower than the 20. So the 15 minute tick mark at the 6 o'clock spot on that subdial could be off-center. 2nd, there may be some play within the chrono wheels that cause the hand to be slightly off at some points. 3rd, the hand wand may be loose on the hand tube, which is a common problem with reps, especially chronographs. Unfortunately, the only way to verify any of these possibilities is to have a watchmaker look the watch over.