[JENKINS-47896] - Add some diagnostics for the failing channel comparison in FilePath

core/src/main/java/hudson/FilePath.java

@@ -2988,7 +2988,7 @@ public final class FilePath implements SerializableOnlyOverRemoting {
     private void writeObject(ObjectOutputStream oos) throws IOException {
         Channel target = getChannelForSerialization();
         if(channel!=target) {
-            throw new IllegalStateException("Can't send a remote FilePath to a different remote channel");
+            throw new IllegalStateException("Can't send a remote FilePath to a different remote channel (current=" + channel + ", target=" + target + ")");
         }
 
         oos.defaultWriteObject();