inview not triggering

[chris-steele]

Subject of the issue

I was alerted to an issue where a text component at the top of a page would not complete. The user lands on the page and the text component is fully visible. It should therefore be complete.

It's possible to replicate this in the latest framework. In my test I looked at c-100 and I had disabled the animation on the parent block.

I have tested in Firefox and Edge and observed the problem in both browsers.

Note also that if I scroll down from the top of the page sometimes c-100 will complete, but sometimes (scrolling slowly with the mouse wheel) it will not complete (see attached animation)

I have tried patching with the fix suggested for #588 but this did not resolve the issue.

[oliverfoster]

Duplicate of #588

can you add this as a review of #589 please?