diff --git a/pgpm/core/__tests__/packaging/round-trip-diff.test.ts b/pgpm/core/__tests__/packaging/round-trip-diff.test.ts
new file mode 100644
index 000000000..b645f63e8
--- /dev/null
+++ b/pgpm/core/__tests__/packaging/round-trip-diff.test.ts
@@ -0,0 +1,28 @@
+import { mergeSqlStatements } from '../../src/packaging/package';
+
+/**
+ * The round-trip check (parse -> deparse -> reparse) must ignore positional
+ * metadata. PG17+ emits list_start/list_end (A_ArrayExpr) and
+ * rexpr_list_start/rexpr_list_end (A_Expr IN lists), which shift whenever the
+ * deparsed SQL is formatted differently than the source.
+ */
+describe('AST round-trip diff detection', () => {
+  it('does not flag ARRAY[...] expressions', async () => {
+    const { diff } = await mergeSqlStatements(
+      `CREATE TABLE things (
+         id int,
+         tags text[] DEFAULT ARRAY['a', 'b', 'c']::text[]
+       );`,
+      {}
+    );
+    expect(diff).toBeUndefined();
+  });
+
+  it('does not flag IN (...) lists', async () => {
+    const { diff } = await mergeSqlStatements(
+      `SELECT * FROM things WHERE id IN (1, 2, 3);`,
+      {}
+    );
+    expect(diff).toBeUndefined();
+  });
+});
diff --git a/pgpm/core/src/packaging/package.ts b/pgpm/core/src/packaging/package.ts
index 4f7851170..8c647b9d8 100644
--- a/pgpm/core/src/packaging/package.ts
+++ b/pgpm/core/src/packaging/package.ts
@@ -22,6 +22,24 @@ export const cleanTree = (tree: any): any => {
   });
 };
 
+/**
+ * Same as cleanTree, but also drops the byte-offset fields PG17+ added for list
+ * expressions (`ARRAY[...]`, `x IN (...)`). They are positional metadata, not
+ * semantics, so they must not count as a round-trip difference. Kept separate
+ * from cleanTree so migration hashes (hashSqlFile) stay stable.
+ */
+export const cleanTreeForDiff = (tree: any): any => {
+  return transformProps(tree, {
+    stmt_len: noop,
+    stmt_location: noop,
+    location: noop,
+    list_start: noop,
+    list_end: noop,
+    rexpr_list_start: noop,
+    rexpr_list_end: noop,
+  });
+};
+
 interface PackageModuleOptions {
   usePlan?: boolean;
   extension?: boolean;
@@ -94,11 +112,11 @@ export const mergeSqlStatements = async (
     sql: `${topLine}${finalSql}`,
   };
 
-  const diff = JSON.stringify(cleanTree(tree1)) !== JSON.stringify(cleanTree(tree2));
+  const diff = JSON.stringify(cleanTreeForDiff(tree1)) !== JSON.stringify(cleanTreeForDiff(tree2));
   if (diff) {
     results.diff = true;
-    results.tree1 = JSON.stringify(cleanTree(tree1), null, 2);
-    results.tree2 = JSON.stringify(cleanTree(tree2), null, 2);
+    results.tree1 = JSON.stringify(cleanTreeForDiff(tree1), null, 2);
+    results.tree2 = JSON.stringify(cleanTreeForDiff(tree2), null, 2);
   }
 
   return results;