[BUG] Incorrect range signalling

[Selur]

Output Luminance stays checked (I set up PC levels), but after some time it stops worlking correctly:

I would need a step-by-step to reproduce it, so I can fix it. 'after some time'

Vapoursynth's Levels can't override for some reason output luminance signalling even if I explicitly tell it to use full range...

That is probably a bug.
Changing "Levels->Range signaling" does change the signaling in the script, but not the output signal.
=> I'll look at that.