This is feature introduced in 2.2.3.
Basically if a web browser connects to litespeed, sends a request, but then closes without waiting or getting any response from litespeed, the request is not logged to "access log". Otherwise, people would be billed for bandwidth they haven't actually pushed.
You can remove the warn level mesages by descreasin the log level.
We give out this message so you know, as web admin, this is happening just in case someone trys to DoS you, at least you have something in your logs.