Hello Sven,
I further worked on the issue with Microsoft and confirmed that a business rule cannot be triggered on roll-up field updates even if you set as entity scope. My goal was to copy the roll-up field value to another field without user interacting with the entity form, in order words, I want copying happens at the background.
Since I don't want to write any single line of custom code to achieve this, I end up using Power Automate Cloud Flows. This is what I did:
1. Create a Cloud Flow. Use "Scheduler" to run the flow every one hour. Since Roll-Up field will update hourly at the minimum, I scheduled this flow to run every one hour.
2. Use CDS connector to pull List Records on the entity. I include "Filter rows" to return only records where the "Roll-Up Field" value is not equals the other field value to minimize the performance issue.
3. Use CDS connector to update each records from step 2.
Attached is the sample flow for your reference.
This has been implemented and running without any issues for quite sometime. I check the timing settings for occurrences of the System Jobs which updates the roll up field and schedule this flow to run after 5 mins. So technically, the copy happens whenever an update at the roll up fields. Once the update happens on the other field, you can use for several other purposes such as triggering a workflow, trigger another flow or use for another roll up on its parent record.
I hope this helps, let me know if you have any question I will be happy to help you.
Thank you,
Preetam
