When importing a 16bit (probably 32 as well) texture it is converted to an 8 bit image.
In all other instances textures maintain bit depth so I think this is worth fixing (particularly for my current workflow
)
If i manually import the png into the model.zip it does work so I assume there are no hard problems here.
I'm on 1.5.1, if this was fixed in 1.5.2 i apologize