#seam

so i bought a 2022 rip curl flash, 3mm neoprene, double‑stitched seams. after about half an hour in 18°C water the left thigh seam starts to split, like a tiny gash. the stitching looks fine at first, then the thread pulls out and you get that "ERR-SEA-07" vibe on the board. i tried re‑reinforcing with polyester thread, same thing. any tips? is it the type of thread, the stitch length, or maybe the surf wax reacting with the neoprene? also, does the surfboard fin placement affect seam stress? need some solid advice, not just generic wetsuit care.