IllegalStateException Method on class was used outside of a Grails application

After upgrade to 2.3 and running Geb functional UI tests, they started to fail with error:

java.lang.IllegalStateException: Method on class [my.Test] was used outside of a Grails application. If running in the context of a test using the mocking API or bootstrap Grails correctly.
       at my.Test.currentGormStaticApi(Test.groovy)
       at my.Test.$static_methodMissing(Test.groovy)
       at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
       at groovy.lang.MetaClassImpl.invokeStaticMissingMethod(MetaClassImpl.java:1372)
       at groovy.lang.MetaClassImpl.invokeStaticMethod(MetaClassImpl.java:1360)
       at groovy.lang.ExpandoMetaClass.invokeStaticMethod(ExpandoMetaClass.java:1123)
       at org.codehaus.groovy.runtime.callsite.StaticMetaClassSite.call(StaticMetaClassSite.java:50)
       at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
       at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
       at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)

After some pretty painful investigation, I found out that problem is when running tests with new fork mode properties, and is easy to solve by removing these options from BuildConfig.groovy:

grails.project.fork = [
    test: [maxMemory: 768, minMemory: 64, debug: false, maxPerm: 256, daemon:true],
    run: [maxMemory: 768, minMemory: 64, debug: false, maxPerm: 256, forkReserve:false],
    war: [maxMemory: 768, minMemory: 64, debug: false, maxPerm: 256, forkReserve:false],
    console: [maxMemory: 768, minMemory: 64, debug: false, maxPerm: 256]
]