Grep + regex issue on shell script

The following command in a job script:

STATUS_ID=$(grep -Eo "Status Code [0-9]+: Done" somefile | grep -Eo "[0-9]+")

Seems to be causing the following ci lint error:

script config should be a string or an array of strings

The command works fine on my bash however when trying to grep the status code via a file containing the line:

Status Code 8484: Done

What is causing the error on gitlab?

@pkaramol Are you able to post the entire .gitlab-ci.yml file?

@markglenfletcher I managed to find the cause of this problem as described here