Terraform pipeline - "integer expression expected" error in log of successful job

Example of pipeline: https://gitlab.developers.cam.ac.uk/uis/devops/webcms/infrastructure/-/jobs/1934710

/scripts-6164-1934710/step_script: line 200: [: : integer expression expected
/scripts-6164-1934710/step_script: line 208: [: : integer expression expected

Need to be fixed it in https://gitlab.developers.cam.ac.uk/uis/devops/continuous-delivery/ci-templates/-/blob/master/terraform-pipeline-base.yml?ref_type=heads