Create Test Execution from Test Plan returns a NullPointerException

There are some uncaught NullPointerException when creating a Test Execution from the Test Plan using the Create Test Execution Button, see following cases

• The creation of the Test Execution fails due to a failed workflow validation (for example a script validation) or due to some other reason. In this case, the null value for the issue must be caught and the user must receive an error with the most details as possible.
• Test Plan custom field does not exists or is not associated with Test Execution issue type (seems OK)
• Test Execution issue type is not associated with the project issue type scheme

How to reproduce the first case:
install scriptrunner and add the following validation on create issue transition, in the project workflow

if(issue.getComponentObjects().size() > 0){
    return true;
} else {
    return false;
}

then, try to create a Test Execution from a Test Plan