I'm surprised there's no discussion of the incoming flags. I'm going to monitor this in the logs with the following:

if (null == intent || null == intent.getAction ()) {
        String source = null == intent ? "intent" : "action";
        Log.e (TAG, source + " was null, flags=" + flags + " bits=" + Integer.toBinaryString (flags));
        return START_STICKY;

Update: Flags were 0 so there was nothing actionable there. I've left the null check in there with no loss of function.

Edit: Ok, I found it in the documentation of START_STICKY of all places! "if there are not any pending start commands to be delivered to the service, it will be called with a null intent object, so you must take care to check for this."