When you request to build a specific platform, it also starts building other platforms. This is not intended behaviour. What's the problem with it? Well, the server returns when the requested platform was done. Suppose you want to download both files (e.g. IPA and APK), then that is not possible because the other is still building.
If this would not work because of backward compatibility maybe add something like --disable-autobuild-trigger, with a corresponding parameter in the developer api.
PhoneGap CLI, node & npm versions
Expected Behaviour
Build specific platform
Actual Behaviour
Builds all platforms
Steps to Reproduce
Just build a specific platform
Reasoning
When you request to build a specific platform, it also starts building other platforms. This is not intended behaviour. What's the problem with it? Well, the server returns when the requested platform was done. Suppose you want to download both files (e.g. IPA and APK), then that is not possible because the other is still building.