Mask VAE Autoencoder inference weird result

[cbe135]

Mask VAE inference seems to like to add a box to inference results. For SlidingWindow inference, the result will be many small boxes in the background. Specifically, the issue seems to be at the encoder end, seeing that with a diffusion-model generated latent, the decoding side generates a normal mask.

Following are in the order of original masks and autoencoder outputs. The autoencoder applied uses default weights mask_generation_autoencoder.pt.