Ive discovered that when i use Sweeping strikes and i switch to Defensive stance, the attack on the 2nd target that jumps has an even further decrease of damage of 10%
so the primary dmg is -10% in defensive stance and the secondary Bounce target is -10% and -10% of the remaining 90% making it -19% on the jump target.
The first target is taking 100 dmg in Battle stance, in defensive its 90 dmg and the bounce target is taking 81 damage.
Both targets were lvl 33 and were the same type of Kurzen jungle fighter as i was conducting the test.
Hope blizzard can fix this, as its a bit odd to be doing -19% dmg when you simply choose to pop sweeping strikes before jumping into defensive.
Also, regarding sweeping strikes, i dont believe the stacks are supposed to be reduced if there is not a bounce target nearby to take damage, i could be wrong but i think this is a classic feature not similar to the orginal game in 2005.
-Aruze
further speculation may conclude that passive abilities that increase damage such as Enrage, death wish and Two handed weapon and one handed weapon specialization may increase the damage recieved by the bounce target, further testing is needed.