From 5e65f7efa85fad169a6263d1bebc1b4f8d3701d4 Mon Sep 17 00:00:00 2001
From: matthewkeil <me@matthewkeil.com>
Date: Thu, 22 Aug 2024 01:27:09 -0400
Subject: [PATCH] fix: calc of pivot slot before slot increment

---
 packages/state-transition/src/util/epochShuffling.ts | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/packages/state-transition/src/util/epochShuffling.ts b/packages/state-transition/src/util/epochShuffling.ts
index ce4ad136c0b6..2342cd327c41 100644
--- a/packages/state-transition/src/util/epochShuffling.ts
+++ b/packages/state-transition/src/util/epochShuffling.ts
@@ -144,8 +144,10 @@ export function computeEpochShuffling(
 }
 
 function calculateDecisionRoot(state: BeaconStateAllForks, epoch: Epoch, beforeSlotIncrement = false): RootHex {
-  const pivotEpoch = beforeSlotIncrement ? epoch : epoch - 1;
-  const pivotSlot = computeStartSlotAtEpoch(pivotEpoch) - 1;
+  let pivotSlot = computeStartSlotAtEpoch(epoch - 1);
+  if (!beforeSlotIncrement) {
+    pivotSlot--;
+  }
   return toRootHex(getBlockRootAtSlot(state, pivotSlot));
 }