DataLoader should not change anything as shown in this example:
data = torch.empty(1000, 1).uniform_(-1, 1)
dataset = TensorDataset(data)
loader = DataLoader(dataset, batch_size=5, shuffle=True)

for data in loader:
    print(data[0].min(), data[0].max())

Could you use a similar check and iterate your Dataset as well as the DataLoader?