yes I believe it is on self.points, but I don’t understand why. I grab points from one part of the tensors (at slice self.surface which is an integer=0 in this example) modify them with lots of intermediate outputs and then put them in self.points[:, :, :, self.surface+1, :]. I get that I can stop the problem with a clone, but I’m trying to understand why there is a problem in the first place.