Uhtred's Chalice flask does not not overflow maximum mana

This is the broken mod:

{ Unique Modifier — Mana }
Mana Recovery from Flasks can Overflow maximum Mana during Effect — Unscalable Value

Here is the full item:


Item Class: Mana Flasks
Rarity: Unique
Uhtred's Chalice
Transcendent Mana Flask
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Quality: +2% (augmented)
Recovers 1113 (augmented) Mana over 11.70 (augmented) Seconds
Consumes 10 of 33 (augmented) Charges on use
Currently has 17 Charges
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Requires: Level 50
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Item Level: 80
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{ Unique Modifier }
283(200-300)% increased Amount Recovered
{ Unique Modifier }
70% reduced Recovery rate
{ Unique Modifier }
55(60-50)% reduced Charges
{ Unique Modifier — Life }
Lose 5% Life per second while you have no Runic Ward during Effect
{ Unique Modifier — Mana }
Mana Recovery from Flasks can Overflow maximum Mana during Effect — Unscalable Value
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Uhtred drank. Verisium burned through his veins.
He gazed at death's face. With all his strength,
he turned instead to the stars, and witnessed Truth.
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Right click to drink. Can only hold charges while in belt. Refill at Wells or by killing monsters.