diff --git a/src/data/ability.ts b/src/data/ability.ts
index ff183a28432..eec1240e1d3 100644
--- a/src/data/ability.ts
+++ b/src/data/ability.ts
@@ -3511,13 +3511,15 @@ export function initAbilities() {
       .attr(PostWeatherChangeAddBattlerTagAttr, BattlerTagType.PROTOSYNTHESIS, 0, WeatherType.SUNNY, WeatherType.HARSH_SUN)
       .attr(UncopiableAbilityAbAttr)
       .attr(UnswappableAbilityAbAttr)
-      .attr(NoTransformAbilityAbAttr),
+      .attr(NoTransformAbilityAbAttr)
+      .partial(), // While setting the tag, the getbattlestat should ignore all modifiers to stats except stat stages
     new Ability(Abilities.QUARK_DRIVE, 9)
       .conditionalAttr(getTerrainCondition(TerrainType.ELECTRIC), PostSummonAddBattlerTagAbAttr, BattlerTagType.QUARK_DRIVE, 0, true)
       .attr(PostTerrainChangeAddBattlerTagAttr, BattlerTagType.QUARK_DRIVE, 0, TerrainType.ELECTRIC)
       .attr(UncopiableAbilityAbAttr)
       .attr(UnswappableAbilityAbAttr)
-      .attr(NoTransformAbilityAbAttr),
+      .attr(NoTransformAbilityAbAttr)
+      .partial(), // While setting the tag, the getbattlestat should ignore all modifiers to stats except stat stages
     new Ability(Abilities.GOOD_AS_GOLD, 9)
       .attr(MoveImmunityAbAttr, (pokemon, attacker, move) => pokemon !== attacker && move.getMove().category === MoveCategory.STATUS)
       .ignorable()
diff --git a/src/data/battler-tags.ts b/src/data/battler-tags.ts
index 183306d5066..0fea80c3759 100644
--- a/src/data/battler-tags.ts
+++ b/src/data/battler-tags.ts
@@ -920,7 +920,7 @@ export class HighestStatBoostTag extends AbilityBattlerTag {
     stats.map(s => pokemon.getBattleStat(s)).reduce((highestValue: integer, value: integer, i: integer) => {
       if (value > highestValue) {
         highestStat = stats[i];
-        return highestValue += value;
+        return value;
       }
       return highestValue;
     }, 0);
diff --git a/src/field/pokemon.ts b/src/field/pokemon.ts
index 606185e0984..b20096513ef 100644
--- a/src/field/pokemon.ts
+++ b/src/field/pokemon.ts
@@ -19,7 +19,7 @@ import { pokemonEvolutions, pokemonPrevolutions, SpeciesFormEvolution, SpeciesEv
 import { reverseCompatibleTms, tmSpecies } from '../data/tms';
 import { DamagePhase, FaintPhase, LearnMovePhase, ObtainStatusEffectPhase, StatChangePhase, SwitchSummonPhase } from '../phases';
 import { BattleStat } from '../data/battle-stat';
-import { BattlerTag, BattlerTagLapseType, EncoreTag, HelpingHandTag, TypeBoostTag, getBattlerTag } from '../data/battler-tags';
+import { BattlerTag, BattlerTagLapseType, EncoreTag, HelpingHandTag, HighestStatBoostTag, TypeBoostTag, getBattlerTag } from '../data/battler-tags';
 import { BattlerTagType } from "../data/enums/battler-tag-type";
 import { Species } from '../data/enums/species';
 import { WeatherType } from '../data/weather';
@@ -600,7 +600,11 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
           ret >>= 1;
         break;
     }
-    
+
+    const highestStatBoost = this.findTag(t => t instanceof HighestStatBoostTag && (t as HighestStatBoostTag).stat === stat) as HighestStatBoostTag;
+    if (highestStatBoost)
+      ret *= highestStatBoost.multiplier;
+
     return Math.floor(ret);
   }