I get the same results, I’m curious to see what PG and others say about it.
I use the MBIT dither in the Ozone 5 plugin rather than the standalone dither that now comes with Wavelab 8…it seems that the noise you show is consistent in both the standalone MBIT plugin and when using Ozone 5.
If you turn on “Monitor 16 Bit Dithering” in the Master Section Tools and go to the very end of a song, it almost sounds like it’s doing some sort of Auto-Blanking in the Low setting (although Auto-Blanking’s not checked). But the Izotope “Type 1 - 1 - Clear” does the same thing, so maybe that’s normal for those two.
Although, if you play full level program material, and pull the Master Section faders down 65-70dB, it doesn’t sound like fully continuous noise. So I don’t know. But it’s doing something, because Low is different than None.