Syntax error in Bash script inlined in YAML anchor for Bitbucket Pipelines

This is a part of my Bitbucket pipeline:

  npm_audit: &npm_audit
    echo "Running npm audit..."
    npm_audit_output=$(npm audit --audit-level=critical)
    if [ $? -ne 0 ]; then
    echo "Critical vulnerabilities found. They must be fixed manually:"
    exit 1
    fi
    npm_audit_output=$(npm audit)
    if [ $? -ne 0 ]; then
    echo "Non-critical vulnerabilities found."
    echo "$npm_audit_output"
    echo "Attempting to fix..."
    npm audit fix
    else
    echo "No vulnerabilities found."
    fi

later called like:

  - step:
      ...
      script:
        - *npm_audit

BB returns:

+ echo "Running npm audit..." npm_audit_output=$(npm audit --audit-level=critical) if [ $? -ne 0 ]; then echo "Critical vulnerabilities found. They must be fixed manually:" exit 1 fi npm_audit_output=$(npm audit) if [ $? -ne 0 ]; then echo "Non-critical vulnerabilities found." echo "$npm_audit_output" echo "Attempting to fix..." npm audit fix else echo "No vulnerabilities found." fi
bash: bashScript5261110360543614450.sh: line 5: syntax error near unexpected token `then'

Why is there a syntax error? ShellCheck is green

And why is the whole script echoed instead of just strings I asked for?

KamilCuk's comment sent me in the right direction. The script was interpreted as a single line and that caused syntex errors. I changed the anchor line to:

npm_audit: &npm_audit |

which made the lines below to be interpreted properly.