diff --git a/packages/cubejs-schema-compiler/test/integration/postgres/primary-key-multi-fact.test.ts b/packages/cubejs-schema-compiler/test/integration/postgres/primary-key-multi-fact.test.ts
new file mode 100644
index 0000000000000..3e14b599e7198
--- /dev/null
+++ b/packages/cubejs-schema-compiler/test/integration/postgres/primary-key-multi-fact.test.ts
@@ -0,0 +1,94 @@
+import { PostgresQuery } from '../../../src/adapter/PostgresQuery';
+import { prepareYamlCompiler } from '../../unit/PrepareCompiler';
+import { dbRunner } from './PostgresDBRunner';
+
+// A cube's own primary key as a query dimension, next to measures from two
+// cubes. The measures split into per-cube subqueries, and the one on the
+// `one` side of the join is multiplied by the fan-out, so it is read through
+// the keys subquery and re-joined to its own cube by that same primary key.
+// The key plays two roles at once - query dimension and re-join key - and has
+// to be projected once: two columns under one alias make the re-join's
+// reference to it ambiguous.
+describe('Primary key dimension on the multi-fact path', () => {
+  jest.setTimeout(200000);
+
+  const { compiler, joinGraph, cubeEvaluator } = prepareYamlCompiler(`
+cubes:
+  - name: cube_a
+    sql_alias: a
+    sql: >
+      SELECT 1 AS id, 100 AS value_a UNION ALL
+      SELECT 2 AS id, 200 AS value_a
+    dimensions:
+      - name: id
+        sql: id
+        type: number
+        primary_key: true
+        public: true
+    measures:
+      - name: measure_a
+        sql: value_a
+        type: sum
+
+  - name: cube_b
+    sql_alias: b
+    sql: >
+      SELECT 10 AS id, 1 AS a_id, '2026-07-05'::timestamp AS date, 5 AS value_b UNION ALL
+      SELECT 11 AS id, 1 AS a_id, '2026-07-10'::timestamp AS date, 7 AS value_b UNION ALL
+      SELECT 12 AS id, 2 AS a_id, '2026-07-15'::timestamp AS date, 9 AS value_b
+    joins:
+      - name: cube_a
+        relationship: many_to_one
+        sql: "{CUBE.a_id} = {cube_a.id}"
+    dimensions:
+      - name: id
+        sql: id
+        type: number
+        primary_key: true
+      - name: a_id
+        sql: a_id
+        type: number
+      - name: date
+        sql: date
+        type: time
+    measures:
+      - name: measure_b
+        sql: value_b
+        type: sum
+    `);
+
+  async function runQuery(q) {
+    await compiler.compile();
+    const query = new PostgresQuery({ joinGraph, cubeEvaluator, compiler }, q);
+    return dbRunner.testQuery(query.buildSqlAndParams());
+  }
+
+  it('primary key dimension next to measures from two cubes', async () => {
+    // measure_a must be counted once per cube_a row despite the two cube_b
+    // rows that share a_id = 1.
+    expect(await runQuery({
+      measures: ['cube_b.measure_b', 'cube_a.measure_a'],
+      dimensions: ['cube_a.id'],
+      timeDimensions: [{
+        dimension: 'cube_b.date',
+        granularity: 'month',
+        dateRange: ['2026-07-01', '2026-07-31'],
+      }],
+      order: [{ id: 'cube_a.id' }],
+      timezone: 'UTC',
+    })).toEqual([
+      {
+        a__id: 1,
+        b__date_month: '2026-07-01T00:00:00.000Z',
+        b__measure_b: '12',
+        a__measure_a: '100',
+      },
+      {
+        a__id: 2,
+        b__date_month: '2026-07-01T00:00:00.000Z',
+        b__measure_b: '9',
+        a__measure_a: '200',
+      },
+    ]);
+  });
+});
diff --git a/rust/cube/cubesqlplanner/cubesqlplanner/src/physical_plan_builder/processors/keys_sub_query.rs b/rust/cube/cubesqlplanner/cubesqlplanner/src/physical_plan_builder/processors/keys_sub_query.rs
index 86a28dbea19f8..28d2365924f86 100644
--- a/rust/cube/cubesqlplanner/cubesqlplanner/src/physical_plan_builder/processors/keys_sub_query.rs
+++ b/rust/cube/cubesqlplanner/cubesqlplanner/src/physical_plan_builder/processors/keys_sub_query.rs
@@ -86,6 +86,20 @@ impl<'a> LogicalNodeProcessor<'a, KeysSubQuery> for KeysSubQueryProcessor<'a> {
 
         if !context.dimensions_query {
             for member in keys_subquery.primary_keys_dimensions().iter() {
+                // A primary key that is also a query dimension is already
+                // projected above. Projecting it again would put two columns
+                // under one alias, making every reference to it from the
+                // enclosing re-join ambiguous. Symbols are matched the way
+                // `Schema::find_column_for_member` matches them, so that the
+                // re-join resolves to the surviving column.
+                let resolved = member.clone().resolve_reference_chain();
+                if keys_subquery
+                    .schema()
+                    .all_dimensions()
+                    .any(|dim| dim.clone().resolve_reference_chain() == resolved)
+                {
+                    continue;
+                }
                 let alias = member.alias();
                 references_builder.resolve_references_for_member(
                     member.clone(),
diff --git a/rust/cube/cubesqlplanner/cubesqlplanner/src/tests/integration/multi_fact.rs b/rust/cube/cubesqlplanner/cubesqlplanner/src/tests/integration/multi_fact.rs
index f7381b4e99a6e..794148bbba6fd 100644
--- a/rust/cube/cubesqlplanner/cubesqlplanner/src/tests/integration/multi_fact.rs
+++ b/rust/cube/cubesqlplanner/cubesqlplanner/src/tests/integration/multi_fact.rs
@@ -598,6 +598,35 @@ async fn test_non_multiplied_multi_join() {
     }
 }
 
+#[tokio::test(flavor = "multi_thread")]
+async fn test_multiplied_aggregate_grouped_by_own_primary_key() {
+    let ctx = create_context();
+
+    // customers.total_lifetime_value is multiplied by the customers→orders
+    // join, so it is read through the keys subquery and re-joined to customers
+    // by customers' primary key. That key is also a query dimension here, so it
+    // plays both roles at once and the keys subquery has to project it exactly
+    // once - two columns under one alias make every reference to it from the
+    // re-join ambiguous.
+    let query = indoc! {"
+        measures:
+          - customers.total_lifetime_value
+          - orders.count
+        dimensions:
+          - customers.id
+          - orders.status
+        order:
+          - id: customers.id
+          - id: orders.status
+    "};
+
+    ctx.build_sql(query).unwrap();
+
+    if let Some(result) = ctx.try_execute_pg(query, SEED).await {
+        insta::assert_snapshot!(result);
+    }
+}
+
 #[tokio::test(flavor = "multi_thread")]
 async fn test_multi_fact_view_two_facts_with_measure_filter() {
     let schema = MockSchema::from_yaml_file("common/integration_multi_fact_view.yaml");
diff --git a/rust/cube/cubesqlplanner/cubesqlplanner/src/tests/integration/snapshots/cubesqlplanner__tests__integration__multi_fact__multiplied_aggregate_grouped_by_own_primary_key.snap b/rust/cube/cubesqlplanner/cubesqlplanner/src/tests/integration/snapshots/cubesqlplanner__tests__integration__multi_fact__multiplied_aggregate_grouped_by_own_primary_key.snap
new file mode 100644
index 0000000000000..91ae41cf6c1ac
--- /dev/null
+++ b/rust/cube/cubesqlplanner/cubesqlplanner/src/tests/integration/snapshots/cubesqlplanner__tests__integration__multi_fact__multiplied_aggregate_grouped_by_own_primary_key.snap
@@ -0,0 +1,12 @@
+---
+source: cubesqlplanner/cubesqlplanner/src/tests/integration/multi_fact.rs
+expression: result
+---
+customers__id | orders__status | customers__total_lifetime_value | orders__count
+--------------+----------------+---------------------------------+--------------
+1             | completed      | 1000.00                         | 2            
+1             | pending        | 1000.00                         | 2            
+2             | completed      | 2000.00                         | 2            
+2             | pending        | 2000.00                         | 1            
+3             | NULL           | 500.00                          | 0            
+4             | completed      | 1500.00                         | 1