This issue is over a year old now. Tested this most of the night to see how it was working, and well..... no change.
Spiked bone shield tooltip: Surround yourself with a whirlwind of bones, absorbing damage equivalent to 19% of your Max Health and returning 40% of damage to melee attackers.
Here is the typical scenario for a 10,865 point shield.
Your shield absorbed 7,313.
Your shield absorbed 1,857.
You hit Melee Fotm with Spiked Bone Shield for 388 damage.
A couple more examples.
Abs: 313
Abs: 1865
Abs: 1726
SB: 147
Should Be: 1561
Abs: 7313
Abs: 1857
SB: 388
Should Be: 3668
Decimal point shifted one position?