Currently we are not able to run reports looking at Activities within Custom Objects. It automatically defaults to Contacts and pulls the activity from the Contact record, not your Custom Object.
We use a few Custom Objects and I am trying to pull a report to show the Notes Body of the notes within our Events records.
We're running into this issue as well and it's quite frustrating!
At the base level, I understand why "activities" require a contact -- a call, an email, a meeting, etc. all need to happen to/with a person. But notes, while technically defined as an engagement/activity, can be added to any object (custom or standard) and do not require a contact. Tasks have been pulled out as their own data source, so I do not understand why notes have not followed suit.
As @HBruce has noted, this makes it effectively impossible to report on notes on custom objects, which feels like a huge limitation in the custom reports tool unless the note *also* has a contact associated to it AND that note is also associated to the contact! See example screenshot below. Completely convoluted.
HubSpot team, please please please please fix this data join issue!
In this example, our custom object is the "LAUNCH Overview." We're able to report on tasks associated with the custom object, but we cannot report on notes (which are defined here as activities) unless they sit on contacts which are associated to the custom objects, rather than looking for notes on the custom object itself.
