TypeError: Cannot read property 'then' of undefined - error when running multiple expect

[aberonni]

I'm getting this error:

  Cannot read property 'then' of undefined
       at new Promise (<anonymous>)
       at process.internalTickCallback (internal/process/next_tick.js:77:7)

It seems that this is happening when running multiple expect inside a loop. For example:

        results.value.forEach(function (element) {
          browser.elementIdAttribute(element.ELEMENT, 'class', function (result) {
            console.log('Checking class: ', result.value);
            browser.expect
              .element(result.value)
              .to.have.attribute('class')
              .which.matches(/.*sb.*/);
          });
        });

An example of how to reproduce is on it's way.

[aberonni]

I've added an example here which can be reproduced by cloning the repo and running npm run test:1938

[phaseen]

Even I have same issue. I am not using expect any where but I am using for loop.
Cannot read property 'then' of undefined
at new Promise ()
at process.internalTickCallback (internal/process/next_tick.js:77:7)