Just in case anyone runs into the issue I described. The error was related to the fmap_decay parameter. I was trying to convert a StyleGAN-Tensorflow trained model that had been checkpointed halfway through the training of the 1024x1024 LOD (level of detail). As a result the alpha/fmap_decay  parameter for the upscaling layer was only @~0.5. That led to me getting strange images, because the code posted here assumes an fmap_decay of 1.0 (which is appropriate for a fully trained LOD). If you plan on using a model that isn’t fully trained/checkpointed at the end of an LOD, try tuning this parameter so that you can get the same quality of image that you are seeing output by the tensorflow model.