So, when you have a blank line in the choice parameter, then even with a default value in the job configuration, this (or one) blank line will be selected by default. In my use-case, the blank line was created by the last \n of the configuration.
Currently, the plugin is keeping all empty lines from the textarea. I do understand from the unit-test class TextareaStringListUtilityTest that it is a desired behavior but it is breaking the build even when the "empty line" is just the end of the choices.
I created the PR-10 to change this behavior.