Error when clicking a button in an iframe using Webdriver IO, Chrome 59 and Chrome Driver 2.30

iframe-button-click-error-webdriver-io.md

From web driver IO's browser.debug() when running my test. The iframe is found and the button is found, but it errors out when you click the button. And the weird thing is, it's not for all buttons in an iframe:

> const frameId = browser.$(iframeSelector).value
> browser.frame(frameId)
{ state: 'success',
  sessionId: 'b7431c7d-a458-490b-a7c2-d733e58f3f85',
  hCode: 307243156,
  value: null,
  class: 'org.openqa.selenium.remote.Response',
  _status: 0 }
  
> const insertButton = browser.$('.btInsert')
> insertButton
{ state: 'success',
  sessionId: 'b7431c7d-a458-490b-a7c2-d733e58f3f85',
  hCode: 1731720605,
  value: { ELEMENT: '48', 'element-6066-11e4-a52e-4f735466cecf': '48' },
  class: 'org.openqa.selenium.remote.Response',
  selector: '.btInsert',
  _status: 0 }
> insertButton.click()
[10:22:11]      Saved screenshot: ERROR_chrome_2017-06-27T14-22-11.700Z.png
Error: An unknown server-side error occurred while processing the command.
    at evalmachine.<anonymous>:1:-48
    at ContextifyScript.Script.runInThisContext (vm.js:25:33)
    at Object.runInThisContext (vm.js:97:38)
    at node_modules/webdriverio/build/lib/commands/debug.js:54:43
    at elementIdClick("48") - click.js:20:22