We have several components to build in one Jenkins job calling the xCode plugin several times
The first two builds work, however the 3rd instance of the build gets stuck after the clean and never gets to the build step
First build:
[openssl-ios] $ /usr/bin/xcodebuild -version
Xcode 6.0.1
Build version 6A317
Cleaning build directory: /Users/Jenkins/Ansible/Mobile3rdParty/openssl-ios/build/Release-iphoneos
===========================================================
== Available provisioning profiles
[openssl-ios] $ /usr/bin/security find-identity -p codesigning -v
1) A0C22EDB47D2DFC413DCD56967B86D28B1374342 "Developer ID Application: Siemens Enterprise Communications GmbH & Co. KG"
2) C19DB47077CAC502936224069C5218D77D163404 "iPhone Developer: Simon Hall (BDNNEYZ3AQ)"
3) F25A1E6F9A4774208A8C590C1953493BDEE6F005 "iPhone Distribution: Siemens Enterprise Communications, Inc."
3 valid identities found
== Available SDKs
[openssl-ios] $ /usr/bin/xcodebuild -showsdks
OS X SDKs:
OS X 10.9 -sdk macosx10.9

iOS SDKs:
iOS 8.0 -sdk iphoneos8.0

iOS Simulator SDKs:
Simulator - iOS 8.0 -sdk iphonesimulator8.0

== Available schemes
[openssl-ios] $ /usr/bin/xcodebuild -list -project openssl.xcodeproj
Information about project "openssl":
Targets:
crypto
ssl

Build Configurations:
Debug
Release
Distribution

If no build configuration is specified and -scheme is not passed then "Release" is used.

Schemes:
crypto
ssl
===========================================================
Going to invoke xcodebuild:target: ALL, sdk: DEFAULT, project: openssl.xcodeproj, configuration: Release, clean: YES, archive:NO, symRoot: DEFAULT, configurationBuildDir: DEFAULT, codeSignIdentity: DEFAULT
[openssl-ios] $ /usr/bin/xcodebuild -alltargets -project openssl.xcodeproj -configuration Release clean build
=== CLEAN TARGET crypto OF PROJECT openssl WITH CONFIGURATION Release ===

Second build:
Cleaning build directory: /Users/Jenkins/Ansible/Mobile3rdParty/ZipArchive/build/Release-iphoneos
===========================================================
== Available provisioning profiles
[ZipArchive] $ /usr/bin/security find-identity -p codesigning -v
1) A0C22EDB47D2DFC413DCD56967B86D28B1374342 "Developer ID Application: Siemens Enterprise Communications GmbH & Co. KG"
2) C19DB47077CAC502936224069C5218D77D163404 "iPhone Developer: Simon Hall (BDNNEYZ3AQ)"
3) F25A1E6F9A4774208A8C590C1953493BDEE6F005 "iPhone Distribution: Siemens Enterprise Communications, Inc."
3 valid identities found
== Available SDKs
[ZipArchive] $ /usr/bin/xcodebuild -showsdks
OS X SDKs:
OS X 10.9 -sdk macosx10.9

iOS SDKs:
iOS 8.0 -sdk iphoneos8.0

iOS Simulator SDKs:
Simulator - iOS 8.0 -sdk iphonesimulator8.0

== Available schemes
[ZipArchive] $ /usr/bin/xcodebuild -list -project ZipArchive.xcodeproj
Information about project "ZipArchive":
Targets:
ZipArchive

Build Configurations:
Debug
Distribution
Release

If no build configuration is specified and -scheme is not passed then "Debug" is used.

Schemes:
ZipArchive
===========================================================
Going to invoke xcodebuild:target: ZipArchive, sdk: DEFAULT, project: ZipArchive.xcodeproj, configuration: Release, clean: YES, archive:NO, symRoot: DEFAULT, configurationBuildDir: DEFAULT, codeSignIdentity: DEFAULT
[ZipArchive] $ /usr/bin/xcodebuild -target ZipArchive -project ZipArchive.xcodeproj -configuration Release clean build
=== CLEAN TARGET ZipArchive OF PROJECT ZipArchive WITH CONFIGURATION Release ===

Third build:
Cleaning build directory: /Users/Jenkins/Ansible/Mobile3rdParty/WebRTC/trunk/build/Release-iphoneos
===========================================================
== Available provisioning profiles
[trunk] $ /usr/bin/security find-identity -p codesigning -v
1) A0C22EDB47D2DFC413DCD56967B86D28B1374342 "Developer ID Application: Siemens Enterprise Communications GmbH & Co. KG"
2) C19DB47077CAC502936224069C5218D77D163404 "iPhone Developer: Simon Hall (BDNNEYZ3AQ)"
3) F25A1E6F9A4774208A8C590C1953493BDEE6F005 "iPhone Distribution: Siemens Enterprise Communications, Inc."
3 valid identities found
== Available SDKs
[trunk] $ /usr/bin/xcodebuild -showsdks
OS X SDKs:
OS X 10.9 -sdk macosx10.9

iOS SDKs:
iOS 8.0 -sdk iphoneos8.0

iOS Simulator SDKs:
Simulator - iOS 8.0 -sdk iphonesimulator8.0

== Available schemes
[trunk] $ /usr/bin/xcodebuild -list -project all.xcodeproj
Information about project "all":
Targets:
All

Build Configurations:
Debug
Profile
Release

If no build configuration is specified and -scheme is not passed then "Debug" is used.

Build is stuck
It is called with configuration Release and target All but never kicks off the real build

Let me know if I need to provide more information