I can reproduce on linux:
❯ conda update -n base -c defaults conda
❯ conda create -n 150and050 python=3.8
❯ conda activate 150and050
❯ conda install -c pytorch pytorch
❯ python -c "import torch; print(torch.__version__);"

ModuleNotFoundError: No module named 'torch'

❯ conda install -c pytorch torchaudio

installs 0.4.0 and downgrades to 1.4.0

❯ python -c "import torch; print(torch.__version__);"

ModuleNotFoundError: No module named 'torch'

❯ python -c "import torchaudio; print(torchaudio.__version__);"

ModuleNotFoundError: No module named 'torchaudio'