diff --git a/src/renderer/components/sidebar/GlobalTaskList.tsx b/src/renderer/components/sidebar/GlobalTaskList.tsx
index 3749a364..46404ca6 100644
--- a/src/renderer/components/sidebar/GlobalTaskList.tsx
+++ b/src/renderer/components/sidebar/GlobalTaskList.tsx
@@ -210,12 +210,14 @@ interface SidebarTeamsDerived {
 }
 
 let cachedSidebarTeamsSignature: string | null = null;
+let cachedSidebarTeamsSource: readonly TeamSummary[] | null = null;
 let cachedSidebarTeamsDerived: SidebarTeamsDerived = {
   identityKey: '',
   filterTeams: [],
   statusSummaries: [],
   memberColorByTeam: new Map(),
 };
+let cachedLeadOfflineTeamsSource: Partial<Record<string, LeadActivityState>> | null = null;
 let cachedLeadOfflineTeamsSignature = '';
 let cachedLeadOfflineTeamNames: string[] = [];
 
@@ -255,6 +257,10 @@ function buildTeamNamesIdentityKey(teams: readonly TeamSummary[]): string {
 function selectLeadOfflineTeamNames(
   leadActivityByTeam: Partial<Record<string, LeadActivityState>>
 ): string[] {
+  if (leadActivityByTeam === cachedLeadOfflineTeamsSource) {
+    return cachedLeadOfflineTeamNames;
+  }
+
   const offlineTeamNames: string[] = [];
   for (const [teamName, activity] of Object.entries(leadActivityByTeam)) {
     if (activity === 'offline') {
@@ -269,17 +275,24 @@ function selectLeadOfflineTeamNames(
   }
 
   if (signature === cachedLeadOfflineTeamsSignature) {
+    cachedLeadOfflineTeamsSource = leadActivityByTeam;
     return cachedLeadOfflineTeamNames;
   }
 
+  cachedLeadOfflineTeamsSource = leadActivityByTeam;
   cachedLeadOfflineTeamsSignature = signature;
   cachedLeadOfflineTeamNames = offlineTeamNames;
   return cachedLeadOfflineTeamNames;
 }
 
 function selectSidebarTeamsDerived(teams: readonly TeamSummary[]): SidebarTeamsDerived {
+  if (teams === cachedSidebarTeamsSource) {
+    return cachedSidebarTeamsDerived;
+  }
+
   const signature = buildSidebarTeamsSignature(teams);
   if (signature === cachedSidebarTeamsSignature) {
+    cachedSidebarTeamsSource = teams;
     return cachedSidebarTeamsDerived;
   }
 
@@ -290,6 +303,7 @@ function selectSidebarTeamsDerived(teams: readonly TeamSummary[]): SidebarTeamsD
     }
   }
 
+  cachedSidebarTeamsSource = teams;
   cachedSidebarTeamsSignature = signature;
   cachedSidebarTeamsDerived = {
     identityKey: buildTeamNamesIdentityKey(teams),
diff --git a/src/renderer/components/team/MemberBadge.tsx b/src/renderer/components/team/MemberBadge.tsx
index a45dfc4c..fb5981c2 100644
--- a/src/renderer/components/team/MemberBadge.tsx
+++ b/src/renderer/components/team/MemberBadge.tsx
@@ -34,6 +34,18 @@ interface MemberBadgeProps {
 }
 
 const EMPTY_TEAM_MEMBERS: readonly ResolvedTeamMember[] = [];
+const memberAvatarMapCache = new WeakMap<readonly ResolvedTeamMember[], Map<string, string>>();
+
+function getCachedMemberAvatarMap(members: readonly ResolvedTeamMember[]): Map<string, string> {
+  const cached = memberAvatarMapCache.get(members);
+  if (cached) {
+    return cached;
+  }
+
+  const next = buildMemberAvatarMap(members);
+  memberAvatarMapCache.set(members, next);
+  return next;
+}
 
 /**
  * Reusable member avatar + colored name badge.
@@ -61,7 +73,7 @@ export const MemberBadge = memo(
         ? selectResolvedMembersForTeamName(s, effectiveAvatarTeamName)
         : EMPTY_TEAM_MEMBERS
     );
-    const avatarMap = useMemo(() => buildMemberAvatarMap(teamMembers), [teamMembers]);
+    const avatarMap = useMemo(() => getCachedMemberAvatarMap(teamMembers), [teamMembers]);
     const avatarSize = size === 'md' ? 32 : size === 'sm' ? 24 : 18;
     const avatarClass = size === 'md' ? 'size-6' : size === 'sm' ? 'size-5' : 'size-4';
     const textClass = size === 'md' ? 'text-xs' : size === 'sm' ? 'text-[10px]' : 'text-[9px]';
diff --git a/src/renderer/components/team/messages/MessagesPanel.tsx b/src/renderer/components/team/messages/MessagesPanel.tsx
index a0e4e449..be000af3 100644
--- a/src/renderer/components/team/messages/MessagesPanel.tsx
+++ b/src/renderer/components/team/messages/MessagesPanel.tsx
@@ -114,6 +114,7 @@ interface TeamMentionEntry {
 }
 
 let cachedTeamMentionSignature = '';
+let cachedTeamMentionSource: readonly TeamSummary[] | null = null;
 let cachedTeamMentionMeta: TeamMentionMeta = {
   teamNames: EMPTY_TEAM_NAMES,
   teamColorByName: EMPTY_TEAM_COLOR_MAP,
@@ -142,8 +143,13 @@ function getTeamMentionSignature(teams: readonly TeamSummary[]): string {
 }
 
 function selectMessagesPanelTeamMentionMeta(teams: readonly TeamSummary[]): TeamMentionMeta {
+  if (teams === cachedTeamMentionSource) {
+    return cachedTeamMentionMeta;
+  }
+
   const signature = getTeamMentionSignature(teams);
   if (signature === cachedTeamMentionSignature) {
+    cachedTeamMentionSource = teams;
     return cachedTeamMentionMeta;
   }
 
@@ -157,6 +163,7 @@ function selectMessagesPanelTeamMentionMeta(teams: readonly TeamSummary[]): Team
     .sort(compareTeamMentionEntries);
 
   if (entries.length === 0) {
+    cachedTeamMentionSource = teams;
     cachedTeamMentionSignature = signature;
     cachedTeamMentionMeta = {
       teamNames: EMPTY_TEAM_NAMES,
@@ -180,6 +187,7 @@ function selectMessagesPanelTeamMentionMeta(teams: readonly TeamSummary[]): Team
     }
   }
 
+  cachedTeamMentionSource = teams;
   cachedTeamMentionSignature = signature;
   cachedTeamMentionMeta = { teamNames, teamColorByName };
   return cachedTeamMentionMeta;