Unless my recollection is failing Posts to Members used to be a "recorded activity", with Post (or message) to Member being in the drop - down list of individual activities.
Having had to send a couple this evening there is no sign of them in the Activity list and no relevant option in the drop - down although "Post to Member" appears in my Email Delivery History based on Bcc Moderators.
Is it (a) my memory playing tricks or (b) has this activity disappeared from the list? If the latter was it deliberate or a bug?
I cannot spot anything in any recent Update message.