The spec says:

The container must validate all injection points of all enabled beans and of all other Java EE component classes supporting
injection when the application is initialized to ensure that there are no unsatisfied or unresolvable ambiguous dependen-
cies. If an unsatisfied or unresolvable ambiguous dependency exists, the container automatically detects the problem and
treats it as a deployment problem.

This should be clarified to also include validation of injection points of observer and disposer methods of enabled beans.