diff --git a/server/src/__tests__/execution-workspace-policy.test.ts b/server/src/__tests__/execution-workspace-policy.test.ts
index a52fba4e..71ef6192 100644
--- a/server/src/__tests__/execution-workspace-policy.test.ts
+++ b/server/src/__tests__/execution-workspace-policy.test.ts
@@ -3,6 +3,7 @@ import {
   buildExecutionWorkspaceAdapterConfig,
   defaultIssueExecutionWorkspaceSettingsForProject,
   gateProjectExecutionWorkspacePolicy,
+  issueExecutionWorkspaceModeForPersistedWorkspace,
   parseIssueExecutionWorkspaceSettings,
   parseProjectExecutionWorkspacePolicy,
   resolveExecutionWorkspaceMode,
@@ -142,6 +143,14 @@ describe("execution workspace policy helpers", () => {
     });
   });
 
+  it("maps persisted execution workspace modes back to issue settings", () => {
+    expect(issueExecutionWorkspaceModeForPersistedWorkspace("isolated_workspace")).toBe("isolated_workspace");
+    expect(issueExecutionWorkspaceModeForPersistedWorkspace("operator_branch")).toBe("operator_branch");
+    expect(issueExecutionWorkspaceModeForPersistedWorkspace("shared_workspace")).toBe("shared_workspace");
+    expect(issueExecutionWorkspaceModeForPersistedWorkspace("adapter_managed")).toBe("agent_default");
+    expect(issueExecutionWorkspaceModeForPersistedWorkspace("cloud_sandbox")).toBe("agent_default");
+  });
+
   it("disables project execution workspace policy when the instance flag is off", () => {
     expect(
       gateProjectExecutionWorkspacePolicy(
diff --git a/server/src/services/execution-workspace-policy.ts b/server/src/services/execution-workspace-policy.ts
index 53487324..4f79beb3 100644
--- a/server/src/services/execution-workspace-policy.ts
+++ b/server/src/services/execution-workspace-policy.ts
@@ -132,6 +132,18 @@ export function defaultIssueExecutionWorkspaceSettingsForProject(
   };
 }
 
+export function issueExecutionWorkspaceModeForPersistedWorkspace(
+  mode: string | null | undefined,
+): IssueExecutionWorkspaceSettings["mode"] {
+  if (mode === "isolated_workspace" || mode === "operator_branch" || mode === "shared_workspace") {
+    return mode;
+  }
+  if (mode === "adapter_managed" || mode === "cloud_sandbox") {
+    return "agent_default";
+  }
+  return "shared_workspace";
+}
+
 export function resolveExecutionWorkspaceMode(input: {
   projectPolicy: ProjectExecutionWorkspacePolicy | null;
   issueSettings: IssueExecutionWorkspaceSettings | null;
diff --git a/server/src/services/heartbeat.ts b/server/src/services/heartbeat.ts
index 0694efed..96a42f7e 100644
--- a/server/src/services/heartbeat.ts
+++ b/server/src/services/heartbeat.ts
@@ -45,6 +45,7 @@ import { workspaceOperationService } from "./workspace-operations.js";
 import {
   buildExecutionWorkspaceAdapterConfig,
   gateProjectExecutionWorkspacePolicy,
+  issueExecutionWorkspaceModeForPersistedWorkspace,
   parseIssueExecutionWorkspaceSettings,
   parseProjectExecutionWorkspacePolicy,
   resolveExecutionWorkspaceMode,
@@ -2098,11 +2099,29 @@ export function heartbeatService(db: Db) {
         cleanupReason: null,
       });
     }
-    if (issueId && persistedExecutionWorkspace && issueRef?.executionWorkspaceId !== persistedExecutionWorkspace.id) {
-      await issuesSvc.update(issueId, {
-        executionWorkspaceId: persistedExecutionWorkspace.id,
-        ...(resolvedProjectWorkspaceId ? { projectWorkspaceId: resolvedProjectWorkspaceId } : {}),
-      });
+    if (issueId && persistedExecutionWorkspace) {
+      const nextIssueWorkspaceMode = issueExecutionWorkspaceModeForPersistedWorkspace(persistedExecutionWorkspace.mode);
+      const shouldSwitchIssueToExistingWorkspace =
+        issueRef?.executionWorkspacePreference === "reuse_existing" ||
+        executionWorkspaceMode === "isolated_workspace" ||
+        executionWorkspaceMode === "operator_branch";
+      const nextIssuePatch: Record<string, unknown> = {};
+      if (issueRef?.executionWorkspaceId !== persistedExecutionWorkspace.id) {
+        nextIssuePatch.executionWorkspaceId = persistedExecutionWorkspace.id;
+      }
+      if (resolvedProjectWorkspaceId && issueRef?.projectWorkspaceId !== resolvedProjectWorkspaceId) {
+        nextIssuePatch.projectWorkspaceId = resolvedProjectWorkspaceId;
+      }
+      if (shouldSwitchIssueToExistingWorkspace) {
+        nextIssuePatch.executionWorkspacePreference = "reuse_existing";
+        nextIssuePatch.executionWorkspaceSettings = {
+          ...(issueExecutionWorkspaceSettings ?? {}),
+          mode: nextIssueWorkspaceMode,
+        };
+      }
+      if (Object.keys(nextIssuePatch).length > 0) {
+        await issuesSvc.update(issueId, nextIssuePatch);
+      }
     }
     if (persistedExecutionWorkspace) {
       context.executionWorkspaceId = persistedExecutionWorkspace.id;
diff --git a/ui/src/components/IssueProperties.tsx b/ui/src/components/IssueProperties.tsx
index 053e8e42..935a3b95 100644
--- a/ui/src/components/IssueProperties.tsx
+++ b/ui/src/components/IssueProperties.tsx
@@ -53,6 +53,17 @@ function issueModeForExistingWorkspace(mode: string | null | undefined) {
   return "shared_workspace";
 }
 
+function shouldPresentExistingWorkspaceSelection(issue: Issue) {
+  const persistedMode =
+    issue.currentExecutionWorkspace?.mode
+    ?? issue.executionWorkspaceSettings?.mode
+    ?? issue.executionWorkspacePreference;
+  return Boolean(
+    issue.executionWorkspaceId &&
+    (persistedMode === "isolated_workspace" || persistedMode === "operator_branch"),
+  );
+}
+
 interface IssuePropertiesProps {
   issue: Issue;
   onUpdate: (data: Record<string, unknown>) => void;
@@ -268,10 +279,6 @@ export function IssueProperties({ issue, onUpdate, inline }: IssuePropertiesProp
       ? currentProject?.executionWorkspacePolicy ?? null
       : null;
   const currentProjectSupportsExecutionWorkspace = Boolean(currentProjectExecutionWorkspacePolicy?.enabled);
-  const currentExecutionWorkspaceSelection =
-    issue.executionWorkspacePreference
-    ?? issue.executionWorkspaceSettings?.mode
-    ?? defaultExecutionWorkspaceModeForProject(currentProject);
   const { data: reusableExecutionWorkspaces } = useQuery({
     queryKey: queryKeys.executionWorkspaces.list(companyId!, {
       projectId: issue.projectId ?? undefined,
@@ -298,9 +305,17 @@ export function IssueProperties({ issue, onUpdate, inline }: IssuePropertiesProp
     }
     return Array.from(seen.values());
   }, [reusableExecutionWorkspaces]);
-  const selectedReusableExecutionWorkspace = deduplicatedReusableWorkspaces.find(
-    (workspace) => workspace.id === issue.executionWorkspaceId,
-  );
+  const selectedReusableExecutionWorkspace =
+    deduplicatedReusableWorkspaces.find((workspace) => workspace.id === issue.executionWorkspaceId)
+    ?? issue.currentExecutionWorkspace
+    ?? null;
+  const currentExecutionWorkspaceSelection = shouldPresentExistingWorkspaceSelection(issue)
+    ? "reuse_existing"
+    : (
+        issue.executionWorkspacePreference
+        ?? issue.executionWorkspaceSettings?.mode
+        ?? defaultExecutionWorkspaceModeForProject(currentProject)
+      );
   const projectLink = (id: string | null) => {
     if (!id) return null;
     const project = projects?.find((p) => p.id === id) ?? null;
@@ -680,7 +695,9 @@ export function IssueProperties({ issue, onUpdate, inline }: IssuePropertiesProp
               >
                 {EXECUTION_WORKSPACE_OPTIONS.map((option) => (
                   <option key={option.value} value={option.value}>
-                    {option.label}
+                    {option.value === "reuse_existing" && selectedReusableExecutionWorkspace?.mode === "isolated_workspace"
+                      ? "Existing isolated workspace"
+                      : option.label}
                   </option>
                 ))}
               </select>