Interesting one, this behavior is actually by design, though Microsoft doesn't document it well at all.
Those registration count fields in the Events module are updated by backend system logic built into the Customer Insights Journeys solution itself, not by a visible plugin, rollup field, or Power Automate flow. That's why you can't find anything in your customization layer. It's essentially a black-box internal process.
The reason your counts are drifting is most likely because that backend logic only counts active registrations in a specific status, it doesn't necessarily count all records you'd expect it to. Cancelled, inactive, or certain transitional statuses may be excluded from the count depending on your configuration.
The fact that manually resetting to 0 and adding a registration jumps to 9 tells me the system is recalculating from its own criteria on each update, just not matching what you're seeing in the grid.
A few things worth checking:
- Which registration statuses are actually being counted vs what you're filtering in your view
- Whether any solution updates recently changed the underlying counting logic
- Raising this with Microsoft Support, since it's internal solution logic, they can see exactly what's triggering the recalculation
You're not doing anything wrong here, it's just frustratingly opaque. Hope that points you in the right direction! 😊
