SharePoint List connection changed to DirectQuery

[april23]

I have a PowerBI report and data model that has been published to a Workspace in PowerBI online, intially created on PowerBI desktop.

Recently one of the tables has stopped updating. When digging into it, somehow the data connection changed to a DirectQuery.

The initial data connection was to a SharePoint list online. I have a reference table with unpivoted columns to this original table connected to the list. The initial table is still refreshing, but the reference/unpivoted column table is not. 

From what I'm finding online, this shouldn't even be possible. 

Here is the new data connection: 

I have a really old version of the PowerBI on my desktop, before many many modifications were done by another user. 

Does anyone have any idea how this could have happened and how to prevent it from happening again? I'm assuming there is no way to switch it back without recreating the connection and updating all the visuals on the PowerBi report. 

Is there any way to get the reference table to update from the original table again? 

I'm not sure when it was last working correctly as it was not used over the summer. 

Edit: We do have PowerBI Pro for license. We published online to have the automated refresh, which was still updating the main table. 

[april23]

@lbendlin Thanks for that recommendation. I put in a ticket and was quickly contacted. Unfortunately, without the original pbix file, there is nothing they can do. They were not able to provide a reason how this happened, or how to prevent it from happening again. 

[lbendlin]

You can theoretically poke around in the .bim file and flip a byte here and there, but since you have a Pro license you can open a Pro ticket at https://admin.powerplatform.microsoft.com/newsupportticket/powerbi

and let them help you.