Robocode Editor/Compiler troubles?

Nice! If you can reproduce it, I'd definitely report it. I can't imagine it's intentional those two operations would take different code paths. I've only ever copied JARs into the robots directory.

Oh, I thought this was some other option to add the robot to the repository/cache, but that's actually just the option for extracting the JAR to source files. So you have to extract every JAR for every robot to not get these errors?

I think you are confusing the Import downloaded robot tool with the Extract downloaded robot for editing tool.

Anyway, yeah, it seems I'll have to import each robot individually from now on.

Ahh, you're right of course. I thought those were both options, but I launched Robocode and only saw the one and thought it had just been renamed. But "Extract..." is only offered in the Editor.