diff --git a/src/main/java/kst4contest/controller/ScoreService.java b/src/main/java/kst4contest/controller/ScoreService.java
index f0a191b..6571cfa 100644
--- a/src/main/java/kst4contest/controller/ScoreService.java
+++ b/src/main/java/kst4contest/controller/ScoreService.java
@@ -227,12 +227,11 @@ public final class ScoreService {
             ChatMember chosen = null;
 
             if (preferredCat != null) {
-                for (ChatMember v : variants) {
-                    if (v != null && v.getChatCategory() == preferredCat) {
-                        chosen = v;
-                        break;
-                    }
-                }
+                chosen = variants.stream()
+                        .filter(Objects::nonNull)
+                        .filter(v -> isSameChatCategory(v.getChatCategory(), preferredCat))
+                        .max(Comparator.comparingLong(ChatMember::getActivityTimeLastInEpoch))
+                        .orElse(null);
             }
 
             if (chosen == null) {
@@ -247,6 +246,14 @@ public final class ScoreService {
 
         return representative;
     }
+
+    private static boolean isSameChatCategory(ChatCategory left, ChatCategory right) {
+        return left != null
+                && right != null
+                && left.getCategoryNumber() == right.getCategoryNumber();
+    }
+
+
     /**
      * Projects the immutable score snapshot back into ChatMember display fields so
      * the normal station table can sort/filter by score without knowing the score
diff --git a/src/main/java/kst4contest/view/Kst4ContestApplication.java b/src/main/java/kst4contest/view/Kst4ContestApplication.java
index b64dcd2..2cc73e9 100644
--- a/src/main/java/kst4contest/view/Kst4ContestApplication.java
+++ b/src/main/java/kst4contest/view/Kst4ContestApplication.java
@@ -4291,32 +4291,24 @@ public class Kst4ContestApplication extends Application implements StatusUpdateL
 	}
 
 
-	private ChatMember resolveChatMemberForTopCandidate(kst4contest.controller.ScoreService.TopCandidate c) {
+	private ChatMember resolveChatMemberForTopCandidate(
+			kst4contest.controller.ScoreService.TopCandidate c
+	) {
 
-		String callRaw = c.getCallSignRaw();
-		ChatCategory preferredCategory = c.getPreferredChatCategory();
-
-		// 1) Prefer exact (callRaw + category) match
-		synchronized (chatcontroller.getLst_chatMemberList()) {
-			for (ChatMember m : chatcontroller.getLst_chatMemberList()) {
-				if (m == null) continue;
-				if (m.getCallSignRaw() == null) continue;
-				if (!m.getCallSignRaw().equalsIgnoreCase(callRaw)) continue;
-
-				if (preferredCategory != null && preferredCategory.equals(m.getChatCategory())) {
-					return m;
-				}
-			}
-
-			// 2) Fallback: any variant with the same callsignRaw
-			for (ChatMember m : chatcontroller.getLst_chatMemberList()) {
-				if (m == null) continue;
-				if (m.getCallSignRaw() == null) continue;
-				if (m.getCallSignRaw().equalsIgnoreCase(callRaw)) return m;
-			}
+		if (c == null
+				|| c.getDisplayCallSign() == null
+				|| c.getPreferredChatCategory() == null) {
+			return null;
 		}
 
-		return null;
+		/*
+		 * Resolve the concrete active login by full callsign and category. Falling
+		 * back to callSignRaw could select a different suffix in the same category.
+		 */
+		return chatcontroller.findActiveChatMember(
+				c.getDisplayCallSign(),
+				c.getPreferredChatCategory()
+		);
 	}