default "" does not work on CDS variables in pipeline scripts

default "" does not work on CDS variables in pipeline scripts: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). I'm writing a step script in a CDS pipeline and I want to use a CDS application variable that may or may not be defined. According to the variables doc…

The task

I'm writing a step script in a CDS pipeline and I want to use a CDS application variable that may or may not be defined. According to the [variables doc](docs/content/workflows/pipelines/variables.md), `default` is listed as one of the available helpers, so I tried using it with an empty string as the fallback:

Part of FineEnvs/MiMo-V2.6-RL-harbor-code.