The ParsedRADeploymentProcessor gets the MUTABLE_REGISTRATION_ATTACHMENT from the deployment unit in line 106, that is not set, so it is null.
Then later in line 176 it tries to register statistics for this resource adapter and calls registration.isAllowsOverride() so that a NPE occurs.

I have posted a pull request that omits this registration in case registration is null.
So for every embedded resource adapter statistics will not be available.
Maybe there is a better was to do this but at least it works for me.