Ollie is getting more independent and is trying to tell you he doesn't want to be bothered at that particular moment and you have to respect that, sometimes we ourselves don't want to be bothered but we can convey with words, they use their beak, just don't take offense to it when he does that, just try later and he may be more receptive.
They can have their good days and bad days just like we do and they are not like cats and dogs that pretty much welcome hands on attention at any time, when he bites just say no bite and turn and walk away for a bit then maybe later he will be more receptive.