Yes we've logged the issue - getting bound around the different support teams at the moment with little progress however I do notice the issue has been acknowledged at https://powerbi.microsoft.com/en-us/support/ We are finding it is very intermittant and can work fine for 15 mins or for some users then just be completely unresponsive for others.
The issue still persists for me as well except I don't receive any errors. Once the report is uploaded to the service and the data is refreshed, the report shows no data. I've had an open support ticket with Microsoft for a couple of weeks. I've noticed it only affects reports that use a merge statement. So much time has passed i've had to rebuild quite a few of our reports using sql statements for the joins and loading it into a single table instead of loading multiple tables and merging in Power BI.
I'm having the same issue. It only impacts one report (my newest.) Both last night & tonight the report failed to refresh due to internal service issue. I edited & republished the report during the day today so I would think if the issue were related to the report, it would be fixed now. All my gateways report they are functioning properly. I don't have a merge in my report either.