What level of Vulnerability on Coward's Chain?

Coward's Chain belt says "You are Cursed with Vulnerability", but at what level?
At level 1 its only 15% increased phys damage, but at lvl 20 - its 30%, which is much more impactful

And another question - does "Reduce Effect of Curses on you" affects this curse?

The advanced tool tip says 15% increased phys taken and +25% chance to bleed, which I think corresponds to level 1 vuln. Unsure, why it's not on the wiki, I think by default it might be 1 when not stated otherwise.

I think reduced effect of curse on you mods should lower the effect.