final tiff is just white

[techdoku]

Hi,

I had a Queue Job done this weekend.
Two VRs and five Tiffs 32bit with alpha channel (as I already did before)

There are no errors shown up, the VR was done correctly but when I open the five tiff files ONLY TWO are showing the model.
The other three are just showing white background.
they are all same sice, same resolution, same file size after rendering.