I am having the same problem. Hard start after the engine is hot. It also idles rough when the engine is hot. The fuels trims a in the range of negative 40 to 60. Otherwise the trims are normal before the engine heats up. The dealer did a carbon clean, new plugs, one new coil, new B1S1 oxygen sensor, two new injectors and nothing has changed. I also noticed the LPFP is delivering 11 bars of pressure at idle and it does not change over the range of engine load. It is producing the maximum output pressure regardless of engine load. The service data states that pressure regulator built into the LPFP is defective if the output pressure is too high.
If maximum pressure is sent to the HPFP at idle, the regulator on the HPFP may not be able to dial back the final pressure going into the injectors resulting in negative fuel trims and misfire at idle. I suspect the reason it does not misfire off idle is because the engine is consuming more fuel and the overpressure is less significant under load. I will be installing the LPFP today and will advise if it's corrected.