And I can confirm the fix @Xon suggested works. The user that had the problem reports that all is fine after downloading the zip created with the patched ReleaseBuilder file. And I'm still able to unzip it in Linux without a problem.
I've applied the fix from above to my installation and packaged up the add-ons once more. They look fine in my windows installation, but my colleagues report them broken still when extracting them on Mac. If the fix from above is the one that got implemented, you probably want to look into it once more.