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..940a80854e29b 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
@@ -85,7 +85,7 @@ const toTooltipSummary = (
 
   return {
     child_states: null,
-    max_end_date: dayjs(segment.x[1]).toISOString(),
+    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,
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..c2a99132587ad 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
@@ -237,6 +237,65 @@ describe("transformGanttData", () => {
     expect(result[2]?.state).toBe("success");
   });
 
+  it("carries the task's actual start and end on every segment of the try", () => {
+    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: "2024-03-14T09:58:00+00:00",
+          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: [],
+    });
+
+    expect(result).toHaveLength(3);
+    // The scheduled, queued, and execution bars all report the task's real start_date/end_date so
+    // the tooltip is consistent no matter which segment is hovered (regression from #68174).
+    const expectedEnd = new Date("2024-03-14T10:05:00+00:00").toISOString();
+
+    for (const segment of result) {
+      expect(segment.start_when).toBe("2024-03-14T10:00:00+00:00");
+      expect(segment.end_when).toBe(expectedEnd);
+    }
+  });
+
+  it("uses the current time as end_when on every segment while the task is still running", () => {
+    const result = transformGanttData({
+      allTries: [
+        {
+          end_date: null,
+          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: "running",
+          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: [],
+    });
+
+    // Queued + execution bars, both reporting the same (running) end so the tooltip is consistent.
+    expect(result.length).toBeGreaterThan(0);
+    const [firstEnd] = result.map((segment) => segment.end_when);
+
+    for (const segment of result) {
+      expect(segment.end_when).toBe(firstEnd);
+      expect(segment.end_when).not.toBeUndefined();
+    }
+  });
+
   it("produces 2 segments when only queued_dttm is present", () => {
     const result = transformGanttData({
       allTries: [
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..70885649da06f 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 (end_date, or "now" while running) — consistent across all segments of the same try. */
+  end_when?: string | null;
   isGroup?: boolean | null;
   isMapped?: boolean | null;
   /** Source try times for tooltips (matches TaskInstance `*_when` fields). */
@@ -135,13 +137,6 @@ export const transformGanttData = ({
             const queuedMs = queuedDttm === null ? undefined : dayjs(queuedDttm).valueOf();
             const scheduledMs = scheduledDttm === null ? undefined : dayjs(scheduledDttm).valueOf();
 
-            // Include scheduled/queued/start times in tooltip data whenever the timestamps exist.
-            const tryWhenForTooltip = {
-              ...(scheduledMs === undefined ? {} : { scheduled_when: scheduledDttm }),
-              ...(queuedMs === undefined ? {} : { queued_when: queuedDttm }),
-              ...(startDate === null ? {} : { start_when: startDate }),
-            };
-
             let endMs: number;
 
             if (hasTaskRunning) {
@@ -152,6 +147,17 @@ export const transformGanttData = ({
               endMs = dayjs(endDate).valueOf();
             }
 
+            // Include scheduled/queued/start/end times in tooltip data whenever the timestamps exist.
+            // start_when/end_when are carried on every segment of a try so the tooltip reports the
+            // task's actual start and end on the scheduled and queued bars too, not just the
+            // execution bar's own bounds.
+            const tryWhenForTooltip = {
+              ...(scheduledMs === undefined ? {} : { scheduled_when: scheduledDttm }),
+              ...(queuedMs === undefined ? {} : { queued_when: queuedDttm }),
+              ...(startDate === null ? {} : { start_when: startDate }),
+              ...(startDate === null && !hasTaskRunning ? {} : { end_when: dayjs(endMs).toISOString() }),
+            };
+
             if (scheduledMs !== undefined) {
               const scheduledEndMs =
                 queuedMs ?? startMs ?? (hasTaskRunning || tryRow.state === "scheduled" ? Date.now() : endMs);