Earlier this week I wasted 45 minutes trying to figure out why the software I've been writing was producing Chinese CSVs, before I finally thought to open them in some software other than LibreOffice. Thanks, Libre!
No worries: I'm a developer too; I know these things happen. Given some of the regressions I've been dealing with recently, it was entirely believable that but was in my software -- otherwise I would have cross-checked with something else much earlier!