The servlet API spec reads as follows:

getLocalAddr
public java.lang.String getLocalAddr()The default behavior of this method is to 
return getLocalAddr() on the wrapped request object. 

Specified by:
getLocalAddr in interface ServletRequest
Returns:
a String containing the IP address on which the request was received.
Since: 
2.4 

I tracked down the bug to the following code:

Http11AprProcessor.java 

The action() method which is called with 

ActionCode.ACTION_REQ_LOCAL_ADDR_ATTRIBUTE

assings a hostname instead of an ip address to the localAddr variable 

1050: localAddr = addr.hostname;

which then sets it in the request object

1058: request.localAddr().setString(localAddr);