When we added batching to our download flows we also include the batch number to the file name. This was not unreasonable BUT where it was added did mean that file names could be subtly different between days. Mainly on subsequent days when we reprocess the last 5 or so days, the expectation was the files would be overwritten but potentially a few would not be.

This could cause duplication and will either need some csv files to be removed or wait for invoice end to reprocess all fills during finalization.