Altmer "Spell Recharge" passive is calculating wrongly — providing less mitigation than intended

TheYKcid · February 2019

The passive is supposed to provide 5% mitigation when procced. All forms of %-based mitigation are calculated multiplicatively, and thus whatever damage you received prior to the bonus should simply be reduced to a flat 0.95x. However, testing shows that it is providing less than 5%.

In the overland, an NPC was hitting me for 859 before the passive, 822 after—a reduction of only 4.3%.

To confirm that this wasn't an unintended interaction with one of the %-mitigation CP stars, I also tested in a non-CP environment, with similar results:
An NPC which was hitting for 733 before the passive, hit for 703 subsequently—a reduction of only 4.1% this time.

The mitigation provided by the passive is simply not being computed correctly.

TheYKcid · February 2019

Repost from my other thread in case anyone was worried that I miscalculated the stacking behavior of %-based mitigation sources:

TheYKcid wrote: »

Before anyone interjects—I am aware that %-mitigation "stacks diminishingly" when calculated from a baseline of zero mitigation. However, my conducted tests compared damage taken before & after activating the passive as the only variable, in which case the incoming damage should have been reduced to a flat 0.95x as % sources are calculated multiplicatively. I also tested in a no-CP environment with no other % sources.