I was really shocked with these findings, have no words!
I was testing the BS 10/10 in normal, epic and legendary Uber, TQ 1.16, on satyrs in helos and defiled lvl 65 char.
In legendary, i got around 15% damage reduction. More to this, i didn't observe any difference betwean BS lvl 1 and 10!
In epic, around 25% damage reduction.
Only in normal damage reduction was close to expected.
I have not found the pattern yet, but it is clear the BS does not work as advertized in Epic and Legendary, having much less than expected efficiency.
I urge everyone to test this. We have to find if BS is still bugged, and there can be other damage reduction skills which do not work as we all used to think.