diff --git a/integration-tests/worker/CHANGELOG.md b/integration-tests/worker/CHANGELOG.md
index 59c45bf4b..495dfa912 100644
--- a/integration-tests/worker/CHANGELOG.md
+++ b/integration-tests/worker/CHANGELOG.md
@@ -1,5 +1,14 @@
 # @openfn/integration-tests-worker
 
+## 1.0.95
+
+### Patch Changes
+
+- 84bebf4: Fix an issue where certain error messages are badly processed the runtime & worker. This resulted in cryptic errors like "src.js is not in the SourceMap".
+  - @openfn/engine-multi@1.6.13
+  - @openfn/lightning-mock@2.2.8
+  - @openfn/ws-worker@1.15.4
+
 ## 1.0.94
 
 ### Patch Changes
diff --git a/integration-tests/worker/package.json b/integration-tests/worker/package.json
index 66903fe7f..45b604649 100644
--- a/integration-tests/worker/package.json
+++ b/integration-tests/worker/package.json
@@ -1,7 +1,7 @@
 {
   "name": "@openfn/integration-tests-worker",
   "private": true,
-  "version": "1.0.94",
+  "version": "1.0.95",
   "description": "Lightning WOrker integration tests",
   "author": "Open Function Group <admin@openfn.org>",
   "license": "ISC",
diff --git a/integration-tests/worker/test/exit-reasons.test.ts b/integration-tests/worker/test/exit-reasons.test.ts
index 8ed4a4c27..8088ed244 100644
--- a/integration-tests/worker/test/exit-reasons.test.ts
+++ b/integration-tests/worker/test/exit-reasons.test.ts
@@ -53,6 +53,30 @@ test('crash: syntax error', async (t) => {
   t.regex(error_message, /Unexpected token \(1:9\)$/);
 });
 
+// https://github.com/OpenFn/kit/issues/1045
+test('crash: reference error', async (t) => {
+  const attempt = {
+    id: crypto.randomUUID(),
+    jobs: [
+      {
+        name: 'x', // important!
+        adaptor: '@openfn/language-common@latest',
+        body: 'fn((s) => s.err.map(s => s))',
+      },
+    ],
+  };
+
+  const result = await run(attempt);
+
+  const { reason, error_type, error_message } = result;
+  t.is(reason, 'fail');
+  t.is(error_type, 'RuntimeError');
+  t.regex(
+    error_message,
+    /TypeError: Cannot read properties of undefined \(reading \'map\'\)/
+  );
+});
+
 // https://github.com/OpenFn/kit/issues/758
 test('crash: job not found', async (t) => {
   lightning.addDataclip('x', {});
diff --git a/packages/cli/CHANGELOG.md b/packages/cli/CHANGELOG.md
index cb7f015ee..0f5054bb1 100644
--- a/packages/cli/CHANGELOG.md
+++ b/packages/cli/CHANGELOG.md
@@ -1,5 +1,12 @@
 # @openfn/cli
 
+## 1.15.2
+
+### Patch Changes
+
+- Updated dependencies [84bebf4]
+  - @openfn/runtime@1.7.3
+
 ## 1.15.1
 
 ### Patch Changes
diff --git a/packages/cli/package.json b/packages/cli/package.json
index 052f99de5..8201685f5 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@openfn/cli",
-  "version": "1.15.1",
+  "version": "1.15.2",
   "description": "CLI devtools for the OpenFn toolchain",
   "engines": {
     "node": ">=18",
diff --git a/packages/engine-multi/CHANGELOG.md b/packages/engine-multi/CHANGELOG.md
index 09e2e8ef2..4c664fda3 100644
--- a/packages/engine-multi/CHANGELOG.md
+++ b/packages/engine-multi/CHANGELOG.md
@@ -1,5 +1,12 @@
 # engine-multi
 
+## 1.6.13
+
+### Patch Changes
+
+- Updated dependencies [84bebf4]
+  - @openfn/runtime@1.7.3
+
 ## 1.6.12
 
 ### Patch Changes
diff --git a/packages/engine-multi/package.json b/packages/engine-multi/package.json
index 9af5df66d..76c9e7f5f 100644
--- a/packages/engine-multi/package.json
+++ b/packages/engine-multi/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@openfn/engine-multi",
-  "version": "1.6.12",
+  "version": "1.6.13",
   "description": "Multi-process runtime engine",
   "main": "dist/index.js",
   "type": "module",
diff --git a/packages/lightning-mock/CHANGELOG.md b/packages/lightning-mock/CHANGELOG.md
index 8b102324d..a88ef7466 100644
--- a/packages/lightning-mock/CHANGELOG.md
+++ b/packages/lightning-mock/CHANGELOG.md
@@ -1,5 +1,13 @@
 # @openfn/lightning-mock
 
+## 2.2.8
+
+### Patch Changes
+
+- Updated dependencies [84bebf4]
+  - @openfn/runtime@1.7.3
+  - @openfn/engine-multi@1.6.13
+
 ## 2.2.7
 
 ### Patch Changes
diff --git a/packages/lightning-mock/package.json b/packages/lightning-mock/package.json
index 5b9f1af33..c23c17395 100644
--- a/packages/lightning-mock/package.json
+++ b/packages/lightning-mock/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@openfn/lightning-mock",
-  "version": "2.2.7",
+  "version": "2.2.8",
   "private": true,
   "description": "A mock Lightning server",
   "main": "dist/index.js",
diff --git a/packages/runtime/CHANGELOG.md b/packages/runtime/CHANGELOG.md
index 5ab835c6d..3408cf143 100644
--- a/packages/runtime/CHANGELOG.md
+++ b/packages/runtime/CHANGELOG.md
@@ -1,5 +1,11 @@
 # @openfn/runtime
 
+## 1.7.3
+
+### Patch Changes
+
+- 84bebf4: Fix an issue where certain error messages are badly processed the runtime & worker. This resulted in cryptic errors like "src.js is not in the SourceMap".
+
 ## 1.7.2
 
 ### Patch Changes
diff --git a/packages/runtime/package.json b/packages/runtime/package.json
index 75fc92a49..4b9a95112 100644
--- a/packages/runtime/package.json
+++ b/packages/runtime/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@openfn/runtime",
-  "version": "1.7.2",
+  "version": "1.7.3",
   "description": "Job processing runtime.",
   "type": "module",
   "exports": {
diff --git a/packages/runtime/src/util/sourcemap-errors.ts b/packages/runtime/src/util/sourcemap-errors.ts
index 331bc5140..7c91ade65 100644
--- a/packages/runtime/src/util/sourcemap-errors.ts
+++ b/packages/runtime/src/util/sourcemap-errors.ts
@@ -26,8 +26,8 @@ export default async (job: Job, error: RTError) => {
     }
 
     if (error.pos && !isNaN(error.pos.line!)) {
-      // TODO how to handle file name properly here?
-      const src = smc.sourceContentFor('src.js')!.split('\n');
+      const fileName = job.name ? `${job.name}.js` : 'src.js';
+      const src = smc.sourceContentFor(fileName)!.split('\n');
       const line = src[error.pos.line! - 1];
       error.pos.src = line;
     }
diff --git a/packages/runtime/test/util/sourcemap-errors.test.ts b/packages/runtime/test/util/sourcemap-errors.test.ts
index f12a71a7e..031aa648a 100644
--- a/packages/runtime/test/util/sourcemap-errors.test.ts
+++ b/packages/runtime/test/util/sourcemap-errors.test.ts
@@ -6,9 +6,9 @@ import { RTError } from '../../src';
 const b = recast.types.builders;
 
 // compile an expression into a function
-const compile = (src: string) => {
+const compile = (src: string, sourceFileName = 'src.js') => {
   const ast = recast.parse(src, {
-    sourceFileName: 'src.js',
+    sourceFileName,
   });
 
   // take the expression and wrap it in a function declaration
@@ -22,12 +22,12 @@ const compile = (src: string) => {
   ast.program.body.push(fn);
 
   return recast.print(fn, {
-    sourceMapName: 'src.map.js',
+    sourceMapName: `${sourceFileName.replace('.js', '.map.js')}`,
   });
 };
 
 test('should write the step name to the error', async (t) => {
-  const { code, map } = compile('x + 1');
+  const { code, map } = compile('x + 1', 'yyy.js');
 
   // create a fake job
   const job = {
diff --git a/packages/ws-worker/CHANGELOG.md b/packages/ws-worker/CHANGELOG.md
index 835c95f54..7a474503e 100644
--- a/packages/ws-worker/CHANGELOG.md
+++ b/packages/ws-worker/CHANGELOG.md
@@ -1,5 +1,13 @@
 # ws-worker
 
+## 1.15.4
+
+### Patch Changes
+
+- Updated dependencies [84bebf4]
+  - @openfn/runtime@1.7.3
+  - @openfn/engine-multi@1.6.13
+
 ## 1.15.3
 
 ### Patch Changes
diff --git a/packages/ws-worker/package.json b/packages/ws-worker/package.json
index 9837e269c..b7be5260b 100644
--- a/packages/ws-worker/package.json
+++ b/packages/ws-worker/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@openfn/ws-worker",
-  "version": "1.15.3",
+  "version": "1.15.4",
   "description": "A Websocket Worker to connect Lightning to a Runtime Engine",
   "main": "dist/index.js",
   "type": "module",