I can't reproduce any problem - I tried refreshing several times and it always triggered 'On ready' (and was never true with 'Is ready' on Start of Layout). There shouldn't be a race condition either because it only initialises the Facebook API in the object's instance onCreate - so the layout is already running and it is already allowed to trigger. So even if it initialises instantly it should still trigger correctly.
I'm not quite clear from your report: is the problem that 'On ready' does not trigger, or it triggers late? If it triggers at all, it's working correctly.