diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4342fce..49749ef 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,8 +12,6 @@ jobs:
       - uses: actions/checkout@v4
 
       - uses: pnpm/action-setup@v4
-        with:
-          version: 9
 
       - uses: actions/setup-node@v4
         with:
@@ -30,4 +28,3 @@ jobs:
 
       - name: Test
         run: pnpm run test
-
diff --git a/src/__tests__/unit/v2-relayer-token-routing.test.ts b/src/__tests__/unit/v2-relayer-token-routing.test.ts
index 34f386c..fbd2ded 100644
--- a/src/__tests__/unit/v2-relayer-token-routing.test.ts
+++ b/src/__tests__/unit/v2-relayer-token-routing.test.ts
@@ -155,6 +155,11 @@ describe('RelayerService.split — pUSD-only collateral', () => {
     expect(capturedExecute!.txs[0].to).toBe(CTF_CONTRACT);
 
     const decoded = CTF_IFACE.decodeFunctionData('splitPosition', capturedExecute!.txs[0].data);
+    // split/merge use pUSD (V2 trading-layer wrapper). Note: this is a
+    // theoretical path — s1 strategy never calls split/merge via Relayer
+    // directly; CLOB Exchange handles split internally during fills. If we
+    // ever DO use split/merge via Relayer, this might need empirical
+    // verification (similar to B14 redeem investigation).
     expect(decoded.collateralToken.toLowerCase()).toBe(POLYGON_CONTRACTS_V2.pUSD.toLowerCase());
   });
 });
@@ -167,6 +172,7 @@ describe('RelayerService.merge — pUSD-only collateral', () => {
     expect(capturedExecute!.txs[0].to).toBe(CTF_CONTRACT);
 
     const decoded = CTF_IFACE.decodeFunctionData('mergePositions', capturedExecute!.txs[0].data);
+    // See split note above re: pUSD vs USDC.e.
     expect(decoded.collateralToken.toLowerCase()).toBe(POLYGON_CONTRACTS_V2.pUSD.toLowerCase());
   });
 });
@@ -175,8 +181,8 @@ describe('RelayerService.merge — pUSD-only collateral', () => {
 // redeem / redeemBatch — pUSD only (V2 trading collateral)
 // ---------------------------------------------------------------------------
 
-describe('RelayerService.redeem — pUSD-only collateral', () => {
-  it('encodes pUSD on the standard CTF redeem path (V2)', async () => {
+describe('RelayerService.redeem — V2 standard CTF redeem uses USDC.e collateral', () => {
+  it('encodes USDC.e on the standard CTF redeem path (B14, 2026-05-10)', async () => {
     const svc = makeService();
     const r = await svc.redeem(TEST_CONDITION_ID, 'YES');
     expect(r.success).toBe(true);
@@ -186,7 +192,11 @@ describe('RelayerService.redeem — pUSD-only collateral', () => {
       'redeemPositions',
       capturedExecute!.txs[0].data
     );
-    expect(decoded.collateralToken.toLowerCase()).toBe(POLYGON_CONTRACTS_V2.pUSD.toLowerCase());
+    // 2026-05-10 (B14): V2 binary CTF markets register USDC.e as the underlying
+    // CTF collateral; pUSD is only the V2 trading-layer wrapper. CTF.redeemPositions
+    // must reference USDC.e to find the split records. See
+    // task-polymarket-v2-redeem-investigation/4-redeem/gap-analysis.md
+    expect(decoded.collateralToken.toLowerCase()).toBe(POLYGON_CONTRACTS_V2.usdcE.toLowerCase());
   });
 
   it('routes through NEG_RISK_ADAPTER for negRisk markets (no collateral arg on adapter)', async () => {
@@ -198,8 +208,8 @@ describe('RelayerService.redeem — pUSD-only collateral', () => {
   });
 });
 
-describe('RelayerService.redeemBatch — pUSD-only collateral', () => {
-  it('encodes pUSD on every standard CTF entry', async () => {
+describe('RelayerService.redeemBatch — V2 standard CTF redeem uses USDC.e collateral', () => {
+  it('encodes USDC.e on every standard CTF entry (B14, 2026-05-10)', async () => {
     const svc = makeService();
     const r = await svc.redeemBatch([
       { conditionId: TEST_CONDITION_ID, outcome: 'YES' },
@@ -211,7 +221,11 @@ describe('RelayerService.redeemBatch — pUSD-only collateral', () => {
     for (const tx of capturedExecute!.txs) {
       expect(tx.to).toBe(CTF_CONTRACT);
       const decoded = CTF_IFACE.decodeFunctionData('redeemPositions', tx.data);
-      expect(decoded.collateralToken.toLowerCase()).toBe(POLYGON_CONTRACTS_V2.pUSD.toLowerCase());
+      // 2026-05-10 (B14): V2 binary CTF markets register USDC.e as the underlying
+    // CTF collateral; pUSD is only the V2 trading-layer wrapper. CTF.redeemPositions
+    // must reference USDC.e to find the split records. See
+    // task-polymarket-v2-redeem-investigation/4-redeem/gap-analysis.md
+    expect(decoded.collateralToken.toLowerCase()).toBe(POLYGON_CONTRACTS_V2.usdcE.toLowerCase());
     }
   });
 });
diff --git a/src/services/relayer-service.ts b/src/services/relayer-service.ts
index 299a2e9..5f93ec9 100644
--- a/src/services/relayer-service.ts
+++ b/src/services/relayer-service.ts
@@ -711,10 +711,17 @@ export class RelayerService {
       to = NEG_RISK_ADAPTER;
     } else {
       // Standard CTF: redeemPositions(collateral, parentCollectionId, conditionId, indexSets)
+      // 2026-05-10: V2 binary CTF markets are still registered with USDC.e as the
+      // underlying collateral (pUSD is the trading wrapper, but the conditional
+      // splits/merges happen at the USDC.e layer). Using pUSD here causes the Safe
+      // call to revert with no on-chain tx (relay returns STATE_FAILED + empty hash).
+      // Empirical proof: probe-relayer-failure.ts experiment 2026-05-10 showed
+      // USDC.e param succeeded (tx 0x488dba6868...) where pUSD param failed across
+      // [1] / [1,2] index sets and NegRiskAdapter.
       const indexSets = outcome === 'YES' ? [1] : [2];
       const ctfInterface = new ethers.utils.Interface(CTF_ABI);
       data = ctfInterface.encodeFunctionData('redeemPositions', [
-        POLYGON_CONTRACTS_V2.pUSD,
+        POLYGON_CONTRACTS_V2.usdcE,
         ethers.constants.HashZero,
         conditionId,
         indexSets,
@@ -837,9 +844,11 @@ export class RelayerService {
         data = negRiskInterface.encodeFunctionData('redeemPositions', [conditionId, amounts]);
         to = NEG_RISK_ADAPTER;
       } else {
+        // 2026-05-10 (B14): V2 standard CTF redeem uses USDC.e collateral.
+        // See task-polymarket-v2-redeem-investigation/4-redeem/gap-analysis.md
         const indexSets = outcome === 'YES' ? [1] : [2];
         data = ctfInterface.encodeFunctionData('redeemPositions', [
-          POLYGON_CONTRACTS_V2.pUSD,
+          POLYGON_CONTRACTS_V2.usdcE,
           ethers.constants.HashZero,
           conditionId,
           indexSets,