If you use Transform Mask transform a layer that extends beyond the bounds of the current image size only a portion of that layer gets transformed.

Reproducible: Always

Steps to Reproduce:
1. Create a document 512 X 512
2.open an image larger than the first document.
3.Copy and paste layer from second document into first document
4. Add Transform Mask on to pasted layer
5. Transform the layer so that all of the contents appear to be within the bounds of the image.


Actual Results:  
Sometimes it is immediately noticeable that only the visible portion of the layer is being transformed.
Sometimes it looks as if the layer was correctly transformed but if you flatten the layer you can see only a portion of the layer was transformed and that there is still content from the transformed layer outside the bounds of the image.

Expected Results:  
The Transform Mask should transform all of the content that it shows it is while previewing. That being the entire layer if nothing is selected.