Spock tests not running after switching to 1.3-groovy-2.5 instead a Nullpointer in ASTTransformation

Issue description

I wrote tests for Java8 code (Spring controllers) with using 1.3-groovy-2.4 version of spock-core and spock-spring and everything was fine.

Now we are changing towards to Java11 / groovy 2.5. So I tried using 1.3-groovy-2.5 but even for minimal tests I get the following error message.

Error:Groovyc: While compiling tests of <project>: Could not instantiate global transform class org.spockframework.compiler.SpockTransform specified at jar:file:/Users/<me>/.m2/repository/org/spockframework/spock-core/1.3-groovy-2.5/spock-core-1.3-groovy-2.5.jar!/META-INF/services/org.codehaus.groovy.transform.ASTTransformation because of exception java.lang.NullPointerException

Additional Environment information

IDE IntelliJ 2019.2

Java/JDK

jdk1.8.0_152

Groovy version

Groovy Version: 2.5.3 JVM: 11.0.2 Vendor: Oracle Corporation OS: Mac OS X

Build tool version

Apache Maven

Apache Maven 3.5.4

Operating System

Mac 10.14 Mojave

IDE

IntelliJ 2019.2

Build-tool dependencies used

Apache Maven

<dependency>
    <groupId>org.spockframework</groupId>
    <artifactId>spock-core</artifactId>
    <version>1.3-groovy-2.5</version>
</dependency>