Hybrid model refresh - it's worth to read the documentation

That's not the question, just to share my experience if it'll be useful for someone.

I had Excel data model published on Power BI with two queries (actually much more, but these two are in questions) -

Q1 which pick-ups data from on-premises SQL server, and

Q2 which takes the data from Excel file published on SPO

At the end of first one it was like =Table.Combine(Source, Q2), other words query to on-premises data and right after the to cloud one. It worked fine before Dec previous year. After that manual refresh worked, schedule one failed to refresh.

More detailed investigation shows what oAuth2 request token (SPO) works fine (by default lives an hour), but ADFS refuses to give refresh token.

Finally I found this article https://powerbi.microsoft.com/en-us/documentation/powerbi-admin-troubleshooting-power-bi-personal-gateway/ which explains the bug in Power BI services.

The solution was to extract Q2 from Q1, i.e. Q1 takes only on-premises data, Q2 only cloud one, and new Q3 which appends Q1 to Q2 gives the result. With such separation scheduled refresh works.