/We can see how torch 1.10.2 does concatenates the windows of all channels after unfold./

The expected behavior, in the code, would be to handle (batch, chans, win_size) per chunk
$\rightarrow$ (batch, chans, win_size, n_chunks).

Thus it has to be reshaped before handling to the NN, from my perspective.
unfolded = unfolded.reshape(batch, channels, self.window_size, -1)