Redundant gradle 'sdist' task run while running tests in loop

I am running test suite (defined in Jenkins DSL) which is a loop of a one test with various parameters. The test depends on gcp, virtualenv and sdist tasks. I have observed that sdist task is running with every loop run what causes redundant generating the same Beam package. 

Here is task run example where you can see sdist is run 4 times.

Here is build.gradle file with the test task.