A bug report for software I don’t run, and so can’t reproduce would be closed anyway. I think ‘steps to reproduce’ is pretty much the first line in a bug report.
If I ran a server that used someone else’s software to allow users to download a file, and someone told me that every 2nd byte needed to be discarded, I like to think I’d investigate and contact the software vendors if required. I wouldn’t tell the user that it’s something they should be doing. I feel like I’m the user in this scenario.