diff --git a/airflow-core/src/airflow/ui/src/layouts/Details/Gantt/GanttTimeline.tsx b/airflow-core/src/airflow/ui/src/layouts/Details/Gantt/GanttTimeline.tsx
index 43c28dba56b52..209a93baed90f 100644
--- a/airflow-core/src/airflow/ui/src/layouts/Details/Gantt/GanttTimeline.tsx
+++ b/airflow-core/src/airflow/ui/src/layouts/Details/Gantt/GanttTimeline.tsx
@@ -18,7 +18,6 @@
  */
 import { Badge, Box, Flex, Text } from "@chakra-ui/react";
 import { useVirtualizer } from "@tanstack/react-virtual";
-import dayjs from "dayjs";
 import type { RefObject } from "react";
 import { Fragment, useLayoutEffect, useRef, useState } from "react";
 import { Link, useLocation, useParams } from "react-router-dom";
@@ -42,6 +41,7 @@ import {
   buildMaxTryByTaskId,
   getGanttSegmentTo,
   gridSummariesToTaskIdMap,
+  toTooltipSummary,
 } from "./utils";
 
 /** Size of the state icon rendered inside each Gantt bar (px). The minimum bar width is derived
@@ -74,32 +74,6 @@ type Props = {
   readonly virtualizerScrollPaddingStart: number;
 };
 
-const toTooltipSummary = (
-  segment: GanttDataItem,
-  node: GridTask,
-  gridSummary: LightGridTaskInstanceSummary | undefined,
-) => {
-  if (gridSummary !== undefined && (node.isGroup ?? node.is_mapped)) {
-    return gridSummary;
-  }
-
-  return {
-    child_states: null,
-    max_end_date: dayjs(segment.x[1]).toISOString(),
-    min_start_date: segment.start_when ?? dayjs(segment.x[0]).toISOString(),
-    state: segment.state ?? null,
-    task_display_name: segment.y,
-    task_id: segment.taskId,
-    try_number: segment.tryNumber,
-    ...(segment.tryNumber === undefined
-      ? {}
-      : {
-          queued_when: segment.queued_when,
-          scheduled_when: segment.scheduled_when,
-        }),
-  };
-};
-
 export const GanttTimeline = ({
   dagId,
   flatNodes,
diff --git a/airflow-core/src/airflow/ui/src/layouts/Details/Gantt/utils.test.ts b/airflow-core/src/airflow/ui/src/layouts/Details/Gantt/utils.test.ts
index d725dfc8be60d..0471de884ac4f 100644
--- a/airflow-core/src/airflow/ui/src/layouts/Details/Gantt/utils.test.ts
+++ b/airflow-core/src/airflow/ui/src/layouts/Details/Gantt/utils.test.ts
@@ -29,6 +29,7 @@ import {
   buildMaxTryByTaskId,
   GANTT_TIME_AXIS_TICK_COUNT,
   gridSummariesToTaskIdMap,
+  toTooltipSummary,
   transformGanttData,
 } from "./utils";
 
@@ -213,10 +214,11 @@ describe("transformGanttData", () => {
   });
 
   it("produces 3 segments when scheduled_dttm and queued_dttm are present", () => {
+    const taskEndDate = "2024-03-14T10:05:00+00:00";
     const result = transformGanttData({
       allTries: [
         {
-          end_date: "2024-03-14T10:05:00+00:00",
+          end_date: taskEndDate,
           is_mapped: false,
           queued_dttm: "2024-03-14T09:59:00+00:00",
           scheduled_dttm: "2024-03-14T09:58:00+00:00",
@@ -235,6 +237,40 @@ describe("transformGanttData", () => {
     expect(result[0]?.state).toBe("scheduled");
     expect(result[1]?.state).toBe("queued");
     expect(result[2]?.state).toBe("success");
+    expect(result.map((segment) => segment.end_when)).toEqual([taskEndDate, taskEndDate, taskEndDate]);
+  });
+
+  it("uses the task end date in tooltips for queued segments", () => {
+    const result = transformGanttData({
+      allTries: [
+        {
+          end_date: "2024-03-14T10:05:00+00:00",
+          is_mapped: false,
+          queued_dttm: "2024-03-14T09:59:00+00:00",
+          scheduled_dttm: null,
+          start_date: "2024-03-14T10:00:00+00:00",
+          state: "success",
+          task_display_name: "task_1",
+          task_id: "task_1",
+          try_number: 1,
+        },
+      ],
+      flatNodes: [{ depth: 0, id: "task_1", is_mapped: false, label: "task_1" }],
+      gridSummaries: [],
+    });
+    const [queuedSegment] = result;
+
+    expect(queuedSegment?.state).toBe("queued");
+    expect(queuedSegment?.x[1]).toBe(dayjs("2024-03-14T10:00:00+00:00").valueOf());
+
+    const summary = toTooltipSummary(
+      queuedSegment as GanttDataItem,
+      { depth: 0, id: "task_1", is_mapped: false, label: "task_1" },
+      undefined,
+    );
+
+    expect(summary.min_start_date).toBe("2024-03-14T10:00:00+00:00");
+    expect(summary.max_end_date).toBe("2024-03-14T10:05:00+00:00");
   });
 
   it("produces 2 segments when only queued_dttm is present", () => {
diff --git a/airflow-core/src/airflow/ui/src/layouts/Details/Gantt/utils.ts b/airflow-core/src/airflow/ui/src/layouts/Details/Gantt/utils.ts
index 9502cd31e7843..88a6717c1e6f5 100644
--- a/airflow-core/src/airflow/ui/src/layouts/Details/Gantt/utils.ts
+++ b/airflow-core/src/airflow/ui/src/layouts/Details/Gantt/utils.ts
@@ -28,6 +28,8 @@ import { renderDuration } from "src/utils/datetimeUtils";
 import { buildTaskInstanceUrl } from "src/utils/links";
 
 export type GanttDataItem = {
+  /** Effective task end_date for tooltips; distinct from segment end for scheduled/queued bars. */
+  end_when?: string | null;
   isGroup?: boolean | null;
   isMapped?: boolean | null;
   /** Source try times for tooltips (matches TaskInstance `*_when` fields). */
@@ -77,6 +79,32 @@ export const gridSummariesToTaskIdMap = (
   return byId;
 };
 
+export const toTooltipSummary = (
+  segment: GanttDataItem,
+  node: GridTask,
+  gridSummary: LightGridTaskInstanceSummary | undefined,
+) => {
+  if (gridSummary !== undefined && (node.isGroup ?? node.is_mapped)) {
+    return gridSummary;
+  }
+
+  return {
+    child_states: null,
+    max_end_date: segment.end_when ?? dayjs(segment.x[1]).toISOString(),
+    min_start_date: segment.start_when ?? dayjs(segment.x[0]).toISOString(),
+    state: segment.state ?? null,
+    task_display_name: segment.y,
+    task_id: segment.taskId,
+    try_number: segment.tryNumber,
+    ...(segment.tryNumber === undefined
+      ? {}
+      : {
+          queued_when: segment.queued_when,
+          scheduled_when: segment.scheduled_when,
+        }),
+  };
+};
+
 export const transformGanttData = ({
   allTries,
   flatNodes,
@@ -152,12 +180,15 @@ export const transformGanttData = ({
               endMs = dayjs(endDate).valueOf();
             }
 
+            const effectiveEndDate = hasTaskRunning ? dayjs(endMs).toISOString() : endDate;
+
             if (scheduledMs !== undefined) {
               const scheduledEndMs =
                 queuedMs ?? startMs ?? (hasTaskRunning || tryRow.state === "scheduled" ? Date.now() : endMs);
 
               if (scheduledEndMs > scheduledMs) {
                 items.push({
+                  end_when: effectiveEndDate,
                   isGroup: false,
                   isMapped: tryRow.is_mapped,
                   state: "scheduled",
@@ -175,6 +206,7 @@ export const transformGanttData = ({
 
               if (queueEndMs > queuedMs) {
                 items.push({
+                  end_when: effectiveEndDate,
                   isGroup: false,
                   isMapped: tryRow.is_mapped,
                   state: "queued",
@@ -192,6 +224,7 @@ export const transformGanttData = ({
               const execEndMs = Math.max(startMs, endMs);
 
               items.push({
+                end_when: effectiveEndDate,
                 isGroup: false,
                 isMapped: tryRow.is_mapped,
                 state: tryRow.state,