Hi,
I've noticed that there're a few fields and actions with the exact same name, but different schema name in the Events module, e.g.
msevtmgt_FinalizeExternalRegistrationRequest and adx_FinalizeExternalRegistrationRequest (actions)
msevtmgt_ProcessExternalRegistrationRequest and adx_ProcessExternalRegistrationRequest (actions)
msevtmgt_allowanonymousregistrations and adx_allowanonymousregistrations (fields)
I'm pretty sure that the msevtmgt_ ones are new and wasn't included in the original release. I'm guessing MS is cleaning up the fields and actions and making sure they're consistent with their prefix, etc. which makes sense. However, this now has resulted in those duplicates (there're probably others that I haven't come across yet) which will confuse the users. Even the MS documentation here is still saying that we'll need to use the adx_ action.
Poking around a but more, I've noticed that there're a plugin that runs and copies over the values of the adx_ fields to the msevtmgt_ fields - go figure! Not sure if they have the same thing that calls msevtmgt_ actions from adx_ actions.
Sigh....end rant.