4.7 : Classloader issues : diff version of JAR used by gradle plugin AND project build

JAR1-common code
JAR2- depends on JAR1-1.2.3 - gradle plugin (in buildscript section)
JAR3 - depends on JAR1-1.6.0 (diff version than JAR2) - business project code AND uses the plugin from JAR2

for the build.gradle of JAR3
It seems that during the build, the use of the plugin (on the ./gradlew commandline) results in the version it requires of JAR1 being loaded AND the same version used for the compile dependency despite specifying a diff version of JAR3. Also tried scope API and implementation with same results.