Streaming insert is a services that allow ingestion of events in real time to BigQuery.
In case you get this error, you are most likely trying to delete data which falls in range of streaming insert window of time being used.
sometimes it take up to 90 mins to ingest the data. thus…. try to delete data from further back in time.
for example:
DELETE FROM `MyProject.MyDataset.MyTable`
WHERE id LIKE '%BigDataDemystified%'
AND time < TIMESTAMP_SUB(CURRENT_TIMESTAMP(), INTERVAL 180 MINUTE)