Multiple Node Exec Instances of Nunit-Console

We're unsure if this is a node problem, or an nunit-problem. We're forced to use nunit 2.6.4 because Xamarin is bad. We're running multiple instances of nunit-console via Node.js child-process.exec, and we're getting errors on teardown:

TearDown : System.InvalidOperationException : Cannot process request because the process (76648) has exited.--TearDown

We're unsure what the problem is. Maybe exec is inadvertently killing the other running processes, or maybe nunit-console 2.6.4 is old enough to be riddle with little bugs like these.

If we run the same code and nunit-console commands but one at a time, things work.

Anybody else run into something like this?

via Ronin