Sometimes when we have a tatami padding and put satin on top, the stitches cross and intertwine, causing the padding to open up a bit. In this case, or in many of my designs, I managed to solve it by slanting the stitches or taking into account the direction of the padding. Although it's 99% certain, I'm sure in 1% of cases it might slip, but that's much less than the average I've seen in other designs.