Weird Black Level on Waveform

Hi all

So I have this night time footage from a BMPCC that I am trying to adjust the black level, etc. But for some reason I cannot go lower than say the 10 line on the vectorscope as if there's a threshold set there.
This doesn't happen with daytime footage from the same camera.
I have my video monitoring set to full data levels. Here's a screenshot of my vectorscope showing that imaginary black-level line:

black level

black-level.jpg (152.52 KiB) Viewed 767 times

Any idea what could be wrong?
Thanks
Gabi

Do you have luts or color transforms going on?

Thanks Walter -

I had a parallel node that had a higher shadow level, and that was the culprit.

Cheers!
Gabi

K!