[Bug] Q&A on Dashboard stops responding - /interpret API calls return 500s

Hello,

We are experiencing a bug where periodically Q&A on Dashboards in the Power BI Service will stop working until we turn Q&A off and then back on again on the dataset we are querying. 

Our dataset uses an Analysis Services live connection.

When it stops working, I opened Chrome DevTools to inspect what network traffic is happening and found a lot of 500s when calling out to https://wabi-us-north-central-b-redirect.analysis.windows.net/explore/interpretation/interpret/.

The request looks like this:

{"Version":2,"Utterance":"gr","Scope":{"InterpretRequestSubscopes":[{"DbMoniker":{"VirtualServerName":"sobe_onpremisevirtualserver","DatabaseName":"aa38c3c7-8eb0-4169-9789-32c69a552ba1"}}]},"Spans":[],"Options":582}

The error response is simply:

{"error":{"code":"Interpretation_UnknownError","pbi.error":{"code":"Interpretation_UnknownError","parameters":{},"details":[]}}}

Successful requests against our other dataset include much more data in the "Spans" property on the request.

I know that a Live Analysis Services Connection Q&A feature for Reports just got pushed out and I'm wondering if that has anything to do with it. We did try out the Preview feature for one of our datasets (but not the one that is failing). Unless it pushes changes at the server level, we don't think it would have to do with that.

I've opened a ticket and will post here if there is a resolution, but wanted to see if anyone else has run into this.