The first attack of the scepter Blood Curse is incorrect. It does 5 ticks of bleed not, the 4 seconds on the tooltip. Tested with no traits and no condition duration.
Lingering Curse trait (33% to all scepter duration) is also mis-labeled. It is doing something more than 33%. It is doing one sec more than multiplying it by 1.33 would yield. 5 sec (blood curse) * 1.33 = 6.65 seconds (no other duration boost) but it has 7 ticks of bleed, not 6.
I also tried getting 23% duration increase with traits, with a 10% bleed sigil for a total of 33% duration, and it yielded 6 seconds of bleed
Summary: Blood Curse tooltip should say 5 seconds of bleed. Lingering Curse is significantly more than 33% boost (bug?)