Microsoft have advised us that this issue has now been remediated

Microsoft have now agreed (on Friday morning Sydney time) that the issue raised by us on Tuesday is an ongoing issue in PowerBI which they believe has been caused by a regression in a recent release.

They are continuing to investigate and plan to implement a short term mitigation and medium term fix. They have also agreed to provide a root cause analysis once they know the cause.

We are receiving reports of degraded performance in PowerBI. There are no code changes on Data Studio and therefore we have logged this is a bug with Microsoft.