This behavior is confusing, but it usually comes from how SharePoint and Power Automate react to column changes.
When you switched your columns back to "Required", SharePoint likely triggered a bulk background update across all items to validate the new schema. If your flow is set to run on "When an item is created or modified", it would fire many times simultaneously.
At the same time, the run history may not show anything immediately. In massive bulk scenarios, runs can be heavily delayed or fail at the trigger level, which makes it look like the flow never executed.
The sequence issue you saw is caused by concurrency (a race condition). Multiple flow instances ran at the exact same millisecond, all of them read the same "previous number" and wrote the same next value. That’s why everything ended up with identical numbers.
Another important point is that there may be a hidden automation. Check for:
- Other flows owned by someone else on the team
- Flows in the "Shared with me" tab
- Old SharePoint Designer workflows (these do not show in Power Automate history but still run)
Recommended Troubleshooting Steps:
- Check all flows: Go to the list, click Integrate -> Power Automate, and look at all flows, including the Shared with me tab.
- Check for legacy workflows: Go to List Settings → Workflow Settings to see if an old SharePoint 2013 workflow is still active.
- The Clean Slate Test: Temporarily turn off your flow and create a test item. If changes or emails still happen, the automation is definitely coming from a duplicate flow or a legacy workflow.
- Fix the Trigger: Update your flow to use "When an item is created" only, or add a Trigger Condition in the flow settings to prevent it from running on minor column modifications.
- Handle Concurrency: For your numbering logic, turn on Concurrency Control (set to 1) in your flow's trigger settings, or use a safer ID generation pattern to prevent duplicate numbers in the future.
Most likely, this is a mix of a bulk SharePoint schema update triggering the flow at scale, combined with a race condition.
Let us know what you find after checking those areas!
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