Comment # 1 on bug 1134688 from Wolfgang Bauer

I can confirm that here, even with the latest Qt5/Plasma/KF5 versions.

But, it is in no way "Critical" IMO...
UTF is the norm since years, so this is rather an edge case, and it only
affects the desktop as you write.

Also, right-clicking and "Open with xxx" works fine here too, so you could use
that as workaround.