I have more or less the same car and the same problem. Itīs been like this for six years now, but only on hot days or if I am in slow traffic for too long.

The limp mode is what causes the stumbling but nobody knows what causes the limp mode. I just ventilate the engine bay for 5-15 minutes depending on outside temp and the car runs fine again. It has nothing to do with engine overheating, but some part, like the crank sensor or another sensor or connection seems to be sensitive to ambient heat. But impossible to diagnose so far....