Getting No implementation of method: :-event of protocol: #'datomic.ion.cast.impl/Cast found for class: nil from my ion in development

Upgraded to 0.9.234 - ion-dev, has anybody else seen this? Doing a regular (cast/event {:msg "MyEvent" ::data {...}})

Doing (require '[datomic.ion.cast :as cast])

Using 0.9.34 ion