Flowable multiinstance completion condition being called twice

Hi, Im using a combination of cardinality and completion condition to achieve multi instance (parallel) executions.
In cardinality field i have passed “${someBean.multiInstanceCardinality(execution)}”, This returns an integer value at runtime

In completion condition, I have passed ${someBean.multiInstanceCompletionCondition(execution)}. This returns either true (if i want to terminate other instances and end multi instance) or false if i want the instance to go on.
However whenever i return false, the method ${someBean.multiInstanceCompletionCondition(execution)} is called twice. I want this method to be only called once once a task is completed. Am i missing something here? Im using flowable version 6.8.0.

Thanks in advance