I have been working on a series of ETL dataflows in a PPU workspace. The source is a cloud SQL server concted through an on premises gateway. Until yesterday I did not have any issues with computed entities; today I tried to edit one and got the error "Computed tables require Premium to refresh. To enable refresh, upgrade this workspace to Premium capacity, or remove this table." I asked for the gateway server to be rebooted and this did not resolve the issue. I created a new PPU workspace, added a new dataflow sourced to the same gateway connection with 2 tables, saved, refreshed, then tried to merge and get the same error; I tried with an onsite SQL server connected through the gateway, and get the same error. I tried connecting to the onsite SQL server without the gateway (Create new connection) and got an "Unexpected error (Session ID: 30ed5e9f-2b87-4954-a402-f69d5e203921, Region: us)". In the meantime, the original dataflows that have scheduled refreshes that include computed entities are working fine. I checked with IT and our only change control since that time was network resiliency / failover testing.
The fix is deployed.