diff --git a/packages/perps-controller/CHANGELOG.md b/packages/perps-controller/CHANGELOG.md
index a8cfc9878c5..e1ad4ff194c 100644
--- a/packages/perps-controller/CHANGELOG.md
+++ b/packages/perps-controller/CHANGELOG.md
@@ -11,6 +11,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Bump `uuid` from `^8.3.2` to `^9.0.1` ([#10117](https://github.com/MetaMask/core/pull/10117))
 
+### Fixed
+
+- Normalize Lighter order timestamps from seconds to milliseconds for client date displays. ([#10187](https://github.com/MetaMask/core/pull/10187))
+- Accept omitted Lighter fill PnL only when the account's validated pre-trade position is zero; retain strict PnL validation for existing positions and malformed supplied values. ([#10187](https://github.com/MetaMask/core/pull/10187))
+
 ## [17.0.0]
 
 ### Changed
diff --git a/packages/perps-controller/src/types/lighter-types.ts b/packages/perps-controller/src/types/lighter-types.ts
index 0f3e19345cb..0eb02b7dfdb 100644
--- a/packages/perps-controller/src/types/lighter-types.ts
+++ b/packages/perps-controller/src/types/lighter-types.ts
@@ -669,9 +669,9 @@ export type LighterRestTrade = {
   bidAccountId: number;
   isMakerAsk: boolean;
   timestamp: number;
-  /** Realized pnl for the ask-side account, signed USDC. */
+  /** Realized pnl for the ask-side account, signed USDC; may be omitted on opens from flat. */
   askAccountPnl?: string;
-  /** Realized pnl for the bid-side account, signed USDC. */
+  /** Realized pnl for the bid-side account, signed USDC; may be omitted on opens from flat. */
   bidAccountPnl?: string;
   /**
    * Taker/maker fees, present when nonzero. The official model types them
@@ -790,6 +790,7 @@ export type LighterApiOrder = {
   reduceOnly: number | boolean;
   status: string;
   orderExpiry: number;
+  /** Unix seconds from order endpoints, unlike millisecond trade timestamps. */
   timestamp: number;
   /**
    * Trigger level for stop-loss/take-profit orders. Note `price` on a
diff --git a/packages/perps-controller/src/utils/lighterAdapter.ts b/packages/perps-controller/src/utils/lighterAdapter.ts
index bb704796e02..2d91c08044f 100644
--- a/packages/perps-controller/src/utils/lighterAdapter.ts
+++ b/packages/perps-controller/src/utils/lighterAdapter.ts
@@ -410,17 +410,6 @@ export function adaptFillFromLighterTrade(
     );
   }
   const fee = '0';
-  const pnl = accountIsAsk ? trade.askAccountPnl : trade.bidAccountPnl;
-  const parsedPnl = parseLighterStrictDecimal(pnl);
-  if (
-    typeof pnl !== 'string' ||
-    parsedPnl === null ||
-    !Number.isFinite(parsedPnl)
-  ) {
-    throw new Error(
-      `${LIGHTER_DATA_INTEGRITY_PREFIX} trade ${trade.tradeId} is missing valid account pnl`,
-    );
-  }
   const isBuy = !accountIsAsk;
   // The account's maker/taker role selects the matching pre-trade position
   // context. Missing context is rejected above instead of becoming neutral
@@ -442,6 +431,21 @@ export function adaptFillFromLighterTrade(
       `${LIGHTER_DATA_INTEGRITY_PREFIX} trade ${trade.tradeId} is missing valid position context`,
     );
   }
+  const accountPnl = accountIsAsk ? trade.askAccountPnl : trade.bidAccountPnl;
+  // The venue omits PnL on opens from flat. Only a validated zero pre-trade
+  // position proves zero realized PnL; never assume it for an existing position.
+  const pnl =
+    accountPnl === undefined && positionBefore === 0 ? '0' : accountPnl;
+  const parsedPnl = parseLighterStrictDecimal(pnl);
+  if (
+    typeof pnl !== 'string' ||
+    parsedPnl === null ||
+    !Number.isFinite(parsedPnl)
+  ) {
+    throw new Error(
+      `${LIGHTER_DATA_INTEGRITY_PREFIX} trade ${trade.tradeId} is missing valid account pnl`,
+    );
+  }
   const direction = deriveLighterFillDirection({
     isBuy,
     size,
@@ -719,7 +723,10 @@ export function adaptOrderFromLighter(
     filledSize: String(filled),
     remainingSize: order.remainingBaseAmount,
     status: adaptOrderStatus(order.status),
-    timestamp: order.timestamp,
+    // Order endpoints report seconds; preserve already-normalized millisecond
+    // inputs. Trade timestamps are a separate millisecond wire contract.
+    timestamp:
+      order.timestamp < 1e12 ? order.timestamp * 1000 : order.timestamp,
     reduceOnly: Boolean(order.reduceOnly),
     providerId: 'lighter',
   };
diff --git a/packages/perps-controller/tests/src/utils/lighterAdapter.test.ts b/packages/perps-controller/tests/src/utils/lighterAdapter.test.ts
index 34d699d5348..a21a7994c5e 100644
--- a/packages/perps-controller/tests/src/utils/lighterAdapter.test.ts
+++ b/packages/perps-controller/tests/src/utils/lighterAdapter.test.ts
@@ -524,7 +524,7 @@ describe('lighterAdapter', () => {
       );
     });
 
-    it('rejects missing account pnl instead of manufacturing zero', () => {
+    it('rejects missing account pnl for an existing position', () => {
       expect(() =>
         adaptFillFromLighterTrade(
           { ...REAL_TRADE, askAccountPnl: undefined },
@@ -534,6 +534,49 @@ describe('lighterAdapter', () => {
       ).toThrow('Invalid Lighter venue data');
     });
 
+    it.each([
+      [true, false, 'Open Short'],
+      [true, true, 'Open Short'],
+      [false, false, 'Open Long'],
+      [false, true, 'Open Long'],
+    ])(
+      'accepts omitted opening pnl for ask=%s maker=%s',
+      (isAsk, isMaker, direction) => {
+        // Testnet trade 20887 omits both PnL fields; the account starts flat.
+        const trade = {
+          ...REAL_TRADE,
+          askAccountPnl: undefined,
+          bidAccountPnl: undefined,
+          isMakerAsk: isAsk === isMaker,
+          makerPositionSizeBefore: isMaker ? '0.00000' : '1',
+          takerPositionSizeBefore: isMaker ? '1' : '0.00000',
+        };
+
+        const fill = adaptFillFromLighterTrade(trade, 'SOL', isAsk ? 28 : 7);
+
+        expect(fill).toMatchObject({ pnl: '0', direction, startPosition: '0' });
+      },
+    );
+
+    it.each(['', 'invalid', '1e999', null])(
+      'rejects supplied malformed opening pnl %s',
+      (pnl) => {
+        const trade = {
+          ...REAL_TRADE,
+          askAccountPnl: pnl,
+          takerPositionSizeBefore: '0',
+        };
+
+        expect(() =>
+          adaptFillFromLighterTrade(
+            trade as unknown as Parameters<typeof adaptFillFromLighterTrade>[0],
+            'SOL',
+            28,
+          ),
+        ).toThrow('Invalid Lighter venue data');
+      },
+    );
+
     it('accepts omitted counterparty pnl while requiring the selected account pnl', () => {
       expect(
         adaptFillFromLighterTrade(
@@ -627,6 +670,19 @@ describe('lighterAdapter', () => {
       timestamp: 1700000000000,
     };
 
+    it.each([
+      [1789088736, 1789088736000],
+      [1789088736000, 1789088736000],
+      [0, 0],
+    ])(
+      'normalizes order timestamp %s to milliseconds',
+      (timestamp, expected) => {
+        const adapted = adaptOrderFromLighter({ ...order, timestamp }, 'BTC');
+
+        expect(adapted.timestamp).toBe(expected);
+      },
+    );
+
     it('maps an open limit buy order', () => {
       const adapted = adaptOrderFromLighter(order, 'BTC');
       expect(adapted).toMatchObject({