The root cause of this bug is definitely pilot error, but read on.

If you have a lifecycle event method in an Extension, and you inadvertently make it static, then the error message you get is this:

org.jboss.weld.exceptions.IllegalStateException: WELD-000143: Container lifecycle event method invoked outside of extension observer method invocation.

It was not at all immediately apparent that the only problem I had was that the method was static. It would be very helpful if this condition could be probed a bit and a better error message delivered.