Mangled is exempt from diminishing returns

Mangled is affected by diminishing returns when applied by perks (but not addons as they're meant to be excluded)

Minor

Always

Steam

Heal speed reductions caused by Mangled as a whole are not working with the diminishing returns system. In the example video I healed Leon with Sloppy Butcher + Leverage, and the heal took 28.6 seconds which is the time it would take without diminishing returns ( 16 / { [ 1 - 0.7 ] * [ 1 - 0.8 ] } ) when it would take 25.4 seconds if diminishing returns was being applied (as mangled would then be 10% penalty instead of 20%).