What’s happening?
Activities displayed in the timeline of a record are incorrectly associated, showing activities related to other records rather than the currently selected record.
Reason:
This can be due to the configuration of the timeline control.
Resolution:
Check the "Activity Rollup type" setting on the timeline component. This setting determines the level of activities displayed within the timeline. Ensure it is configured correctly to display only directly related records or the intended hierarchy of related records.
See the section "Set the activity rollup type in timeline" from Add and configure the timeline control in Power Apps - Power Apps | Microsoft Learn for more information