Hi! I have rechecked everything again.
Salvatore, I'm testing on an up to date buster running kernel 4.17.17-1 and I still see the kernel warning messages and the downloads are breaking and wget still shows this king of messages: 2018-08-29 13:45:31 (122 MB/s) - Read error at byte 1056768/6538880 (Bad address). Retrying. So I see no progresses with newer versions or anything like that. Don't know what are the differences between your setup and mine, maybe it is the file length? What seems to work ok is the workaround of setting EnableSendfile to on, this avoids the original problem I had found on Stretch and also the problems I later found on buster with the kernel warnings and broken downloads. Hope this helps. Regards. -- Manty/BestiaTester -> http://manty.net