Elemental Ailment Avoidance not working when performance drops

Character has 107% elemental ailment avoid chance using stormshroud jewel with chance to avoid shock mageblood flask. This was confirmed with the character defence tab during the map.

Occurred on a permanent delirium t17 abomination map.

Character was repeatedly inflicted with shock, ignite, and chill.

Appears to occur when performance drops due to large packs.

Map linked below, Atlas has at least 85% explicit modifier, delirium, beyond, alva

Item Class: Maps
Rarity: Rare
Forgotten Vine
Abomination Map
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Map Tier: 17
Item Quantity: +126% (augmented)
Item Rarity: +75% (augmented)
Monster Pack Size: +90% (augmented)
More Currency: +70% (augmented)
Quality: +20% (augmented)
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Item Level: 83
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Monster Level: 84
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90% more Monster Life
Monsters have 70% chance to Avoid Elemental Ailments
Area contains Runes of the Searing Exarch
Players have 25% less Area of Effect
The Maven interferes with Players
Map Boss is accompanied by a Synthesis Boss
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Travel to this Map by using it in a personal Map Device. Maps can only be used once.
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Modifiable only with Chaos Orbs