'Xboxing Day' in June was less of an event, more of a casual news drop, it was going to be apart of IGN's Summer of Gaming slipped into one of their livestream, confirmed to be focused on Services/Platform (So OS, Series X, etc.) and rumoured to be where Lockhart would be revealed.
The July event is a proper event, full Xbox Game Studios showcase + 3rd party marketing (so basically their E3).
Ah I see. Thanks for the explanation!