After upgrading our core system to 1.608 (through 1.606) from 1.601, our unit tests have started to hang. They compile fine, but hang when trying to start the simulator.

This was working fine in 1.601.

When running the command in terminal on the local machine, the tests run fine, but run from the JNLP service it hangs. Jenkins seems unable to start the simulator.

The command we have been using is:
/usr/bin/xcodebuild -scheme <SCHEME> -sdk iphonesimulator8.2 -workspace /Users/Shared/Jenkins/Home/workspace/iOS.xcworkspace -configuration Debug build test -destination "platform=iOS Simulator,name=iPhone 5,OS=8.2"

We subsequently upgraded the Xcode plugin from 1.4.5 -> 1.4.8 -> 1.4.5 -> 1.4.8 and found no change. Also, we re-downloaded the JNLP agent and removed/re-installed a build node to try and isolate that too.

[Edit] Added in more specific version information