Data refresh keeps failing when A1 capacity is assigned

We have a Power BI import type dataset in the service that is about 280MB in a .pbix version. Recently we moved from Power BI Workspace collections to Power BI embedded in Azure. 

We assigned the workspace to the dedicated capacity (A1 tier) and we are unable to refresh the data. The error that we get is:

The command has been canceled.. The exception was raised by the IDbCommand interface. Table: XXX.

Anytime we run it, a different table is in the error message. If we scale the tier to A2, or if we unassign the premium capacity, the refresh succeeds always. 

Why is the A1 tier unable to import the data? We don't have any other workspaces assigned to that capacity. And it fails even if no one is using the embedded reports.

How can we optimize the model to be able to refresh the data with A1 tier? Scaling up to A2 tier is more then x2 time expensive and for embedding purposes A1 is quite enough for us.