diff --git a/common/src/main/java/com/viaversion/viaversion/platform/AbstractProtocolDetectorService.java b/common/src/main/java/com/viaversion/viaversion/platform/AbstractProtocolDetectorService.java
index c0787bb5c..40a9e1dfb 100644
--- a/common/src/main/java/com/viaversion/viaversion/platform/AbstractProtocolDetectorService.java
+++ b/common/src/main/java/com/viaversion/viaversion/platform/AbstractProtocolDetectorService.java
@@ -33,14 +33,15 @@ public abstract class AbstractProtocolDetectorService implements ProtocolDetecto
     public int serverProtocolVersion(final String serverName) {
         // Step 1. Check detected
         lock.readLock().lock();
+        final int detectedProtocol;
         try {
-            final int detectedProtocol = detectedProtocolIds.getInt(serverName);
-            if (detectedProtocol != -1) {
-                return detectedProtocol;
-            }
+            detectedProtocol = detectedProtocolIds.getInt(serverName);
         } finally {
             lock.readLock().unlock();
         }
+        if (detectedProtocol != -1) {
+            return detectedProtocol;
+        }
 
         // Step 2. Check config (CME moment?)
         final Map<String, Integer> servers = configuredServers();
@@ -81,6 +82,7 @@ public abstract class AbstractProtocolDetectorService implements ProtocolDetecto
 
     @Override
     public Object2IntMap<String> detectedProtocolVersions() {
+        lock.readLock().lock();
         try {
             return new Object2IntOpenHashMap<>(detectedProtocolIds);
         } finally {