• Version: v4.4.5
• Platform: OS X 10.11.5 (15F34) [Darwin 15.5.0 Darwin Kernel Version 15.5.0: Tue Apr 19 18:36:36 PDT 2016; root:xnu-3248.50.21~8/RELEASE_X86_64 x86_64]
• Subsystem: child_process

I wasn't able to create a code example for this issue, but is happens consistently in our integration tests. We spawn a python process (2.7.10) with binary encoding - eventually we get stderr 'end' & process 'exit' events, but no stdout 'end' or process 'close' events - it seems like it's specific to some of the tests, but not for all. I tested on v4.4.4 (and some other earlier versions) with no similar issues at all - so you might be able to pin point the issue without a proper code example.

a sketch of the code

const process = spawn(pythonPath, command, { encoding: 'binary' } );
process
.on('exit', (code) => { console.log('exit') })
.on('close', (code) => { console.log('close') }) // for some cases this event doesn't arrive