After some investigation, I found the cause to be that they now include the jandex index in their jars. This index contains javax annotations to define the CDI beans. If Weld finds a jandex index, it will use that. However, in EE9 preview mode, it searches for jakarta annotations in that index.The end result was that no CDI beans were found in the Reactive Messaging provider jar.

I've worked around this in my https://github.com/wildfly/wildfly/pull/14953, by adding a method to WeldCapability to ignore the precalculated jandex index for modules containing jars with a jandex index. 

I am mentioning this because the jandex index was added to help with some build time config checking for Quarkus. So it would not surprise me if other SmallRye projects, and maybe other projects consumed by Quarkus follow suit.

My changes have not been reviewed yet, so there might be some small changes but the overall concept will most likely be kept.

Thanks,

Kabir