# Cumulative Layout Shift Changes in M85

## Changes in Chrome 85
Prior to Chrome 85, there was a [bug](https://bugs.chromium.org/p/chromium/issues/detail?id=1088311)
in Cumulative Layout Shift on pages with video elements. Hovering over the video
element so that the thumb slider was visible would result in layout shifts when
it moved. The bug was fixed in Chrome 85. The source code of the change can be
seen [here](https://chromium-review.googlesource.com/c/chromium/src/+/2233310).

## How does this affect a site's metrics?

This change only affects metrics for a very small amount of sites. Desktop sites
with video elements that users hover their mouse over for an extended period of
time will have lower CLS values starting in Chrome 85.

We do not see an impact from this change in our overall metrics, so we believe
the effect on most sites will be minimal.

## When were users affected?

Most users were updated to Chrome 85 the week of August 24, 2020.