I don’t know if this is the same problem, but I just got an autograd error trying to run a small Fastai Tabular model.  I’d appreciate advice about how to track down the problem.
~/anaconda3/envs/fastai/lib/python3.8/site-packages/torch/autograd/__init__.py in backward(tensors, grad_tensors, retain_graph, create_graph, grad_variables)
    123         retain_graph = create_graph
    124 
--> 125     Variable._execution_engine.run_backward(
    126         tensors, grad_tensors, retain_graph, create_graph,
    127         allow_unreachable=True)  # allow_unreachable flag

RuntimeError: Found dtype Short but expected Float
Exception raised from compute_types at /Users/distiller/project/conda/conda-bld/pytorch_1595629449223/work/aten/src/ATen/native/TensorIterator.cpp:183 (most recent call first):
frame #0: c10::Error::Error(c10::SourceLocation, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >) + 169 (0x128c4e199 in libc10.dylib)
frame #1: at::TensorIterator::compute_types(at::TensorIteratorConfig const&) + 3842 (0x121193312 in libtorch_cpu.dylib)
frame #2: at::TensorIterator::build(at::TensorIteratorConfig&) + 618 (0x12119c51a in libtorch_cpu.dylib)
frame #3: at::TensorIterator::TensorIterator(at::TensorIteratorConfig&) + 223 (0x12119c1ff in libtorch_cpu.dylib)
frame #4: at::native::mse_loss_backward_out(at::Tensor&, at::Tensor const&, at::Tensor const&, at::Tensor const&, long long) + 410 (0x120fe7f7a in libtorch_cpu.dylib)