[Affected versions]:

• Firefox Beta Version 66.0b14, Build ID 20190307095232
• Firefox Nightly Version 67.0a1, Build ID 20190314094420

[Affected Platforms]:

• All Windows

[Prerequisites]:

• The "gfx.webrender.all.qualified" boolean pref is set with the "true" value.

[Steps to reproduce]:

1. Open the browser with the profile from prerequisites and navigate to https://www.apple.com/iphone-xr/.
2. Scroll down the page to the "Advanced Face ID" section.
3. Scroll down past the iphone image and observe the behavior.

[Expected result]:

• The transition is smooth as the image enlarges.

[Actual result]:

• The image is jerking while enlarging.

[Notes]:

• I have attached screen recordings of the issue.

This looks similar to some of our other snapping bugs. I don't think it needs to block release.

Can you still reproduce this on Nightly?

I was unable to retest this issue because the https://www.apple.com/iphone-xr/ page is no longer featured and does not contain the affected animation. On the current featured page (https://www.apple.com/iphone-11-pro/) the issue is not reproducible. Tested using Firefox 71.0a1 on Windows 10 x64.