Weird, I suppose that’s an R6 model.
Have you accidentally kept some of the parts of the design transparent? Software often has a colour similar to that for transparency.
Next step is to try it on different models, R15 and Rothro. If it works on that then you know it’s not the shirt.
Just realised my software does support transparency, anyway I exported it as a PNG when I put my shirt on the new template and it showed me nothing different.