Environment details

• OS: CoreOS
• Node.js version: v8.9.4
• npm version: v6.1.0
• @google-cloud/spanner version: v1.4.1

Steps to reproduce

1. Setup db with table which contains a field with a definition as follows:

fieldName ARRAY<STRING(32)>

2. Query said table (I'm doing this in queries with a LIMIT 1000 on them), and call .toJSON() on each returned row
3. Use some validation code like such to detect fields not being converted

if (arrayField && arrayField.length > 0 && arrayField.some(each => typeof each === 'object')) {
  console.log('Object in arrayField');
}

I've added the aforementioned logs to a task and API I suspected was being impacted by this issue and get rows which look like the following next to converted fields:

{
  fieldName: {
    kind: "stringValue",
    stringValue: "value",
  },
}

However a fair amount of requests are still succeeding so this issue does not appear to be constant.