I remember seeing somewhere in a list of changes approximately how much Icebound Fortitude will reduce incoming damage if a person were at 540 defense, but I'm having a hard time finding it. Can anyone help out with this please?
It was in one of the patch notes.
IBF is not 20% and scales with Defense. 540 defense puts it at just about 35% damage reduction.
The glyph for IBF makes it always give at least 30% damage reduction, but doesn't add any to the scaling.
It's almost exactly 41% at 540 def, you can test it yourself by jumping in lava and get exact numbers.