The process of building custom applications and tools that interact with Microsoft SharePoint, including SharePoint Online in Microsoft 365.
The error is accurate: the flow does contain a premium connector, even though the diamond icon is not showing. The Microsoft Dataverse connector is premium (Microsoft's connector reference lists it as Premium), while Send an HTTP request to SharePoint is standard. So it is the Dataverse actions that trigger the check, not the SharePoint one.
Why dev works and test does not: a Developer environment comes with the free Developer Plan, which allows premium connectors in that environment only. Test is a normal sandbox or production environment, so whoever saves or turns on the flow needs a Power Automate Premium licence (or a Power Apps Premium or per-user plan that covers it, or the flow needs a Process licence).
Run As on the button controls which connection is used when the flow runs. It does not change who needs a licence to save or activate the flow, and the error text says save, so the account doing the saving is the one being checked.
What I would check: open the flow in Test, look at Details for the owners and the connections list, and confirm the last person to save or turn it on holds a premium licence in the Microsoft 365 admin centre. If it is an account with the Developer Plan only, assign a Power Automate Premium licence or move ownership to a licensed account. If you cannot licence it, replace the Dataverse actions with a standard option (for example a SharePoint list) so the flow stays standard.
I cannot see a service incident from here. The check runs when a flow is saved, imported or re-enabled, so a flow that has been fine for months can fail the first time it is touched in Test, which would explain why it started yesterday.