Backflushing occurs when your complete/close a work order in the work order close function. It would generate a production tracking record for  material consumption like any other production tracking records, and it should only do that for the material that set to backflush on the product-site record. Since it generates regular production tracking records, you need to make sure the work order closing function is using a correct production tracking entry transaction. You can set this up under the "Setup -> General Parameters -> Parameter values", under Chapter GPA group TRA, and parameter CLEMTSNUM. Typically it's setup to look at the STD entry transaction. If you delete the STD production tracking entry transaction, you will need to make sure that you come here and point it to a different entry transaction, or otherwise, the backflushing will not work.