Mag rendering and Warning icon are out of sync (if “render missing data black” deactivated)

[fm3]

My segmentation layer has only 16-16-4. When deactivating “render missing data black” I would expect to be able to zoom in as far as 2-2-1 and still see the segmentation. However, 8-8-2 is the only “upsampled” mag where the segmentation is still shown.
Conversely, the warning icon “segmentation layer does not have this mag” is shown only in mag1.