I just upgraded to beta 6. I am not quite sure the source of the problem but I will describe as best I can. All was working on 3.0.3...
1. I have a profile with custom fields, used to register for an event.
2. I (admin) and registered user can register for the event, all profile fields show correctly, are filled in, and are entered into the DB table.
3. A very pretty email (who did this? I love the clean html emails!) is sent with all fields filled in.
so far so good.
4. If I "view" the profile, only the basic event status fields are visible. All profile fields (which includes a primary email/name and set of custom fields in custom profile) do not show. Gone. Note that in 3.0.3 these were all visible.
5. If I "view" as the user, likewise, all gone.
and, perhaps not coincidentally...
6. The handlers in Views which pull the title of submissions as well as submission ID (so I can create a link to specific user submissions) are broken/missing.
I am happy to pass on any info, but I am not super tech savvy.