Move toolbar on top
and visit http://bela-lugosi.de
Wait until animation ends.
Should display an ellipse sized over the whole viewport.
Ellipse is cropped on bottom.
no
no
this happens with many more websites and even the no internet connection page
Hello, I can confirm this issue using the latest version from Playstore of Firefox Preview Nightly 1/8 build #20080617 and Firefox Preview RC 3.0.1 build #13502256.
This seems to have been fixed. QA for conformation. Thank you!
@mcarare I wasn't able to reproduce the issue on Nightly 9/25 with Pixel 3 (Android 11).
@s-ankur based on your comment, can you check on the other websites you were mentioning? or some STR will be helpful, and I can check. Thank you!
I don't remember the other websites but I can still see this on

Nightly 200925 06:01 (Build #2015765939)
AC: 61.0.20200923190103, 50960c843
GV: 83.0a1-20200922094538
AS: 63.0.0
You just need to attempt to scroll during the loading
Also able to see this on a different reload

Thank you all!
Seems to be a layout issue in GeckoView for which I created https://bugzilla.mozilla.org/show_bug.cgi?id=1668845
This issue is reproducible on Nightly 201204 GV 85 from 12/4 with Pixel 2 (Android 9).
I will keep the qa:needed label to check this issue again on Nightly 12/7.
This issue is reproducible on Nightly 201207 GV 85 from 12/7 with Pixel 2 (Android 9), by scrolling the page after the page is loaded.
I will remove the qa:needed label for now.

Thank you Eliza
I can reproduce it also

Thinking that maybe after migrating the top toolbar to use a similar behavior as the bottom one (https://github.com/mozilla-mobile/fenix/issues/10686) this issue might be fixed.
Asking @hiikezoe if we should reopen the GV ticket, if there's anything else that can be done on GV.
If this issue doesn't happen with the bottom toolbar, it's probably a Fenix issue.
Then let's have this waiting for when we unify the top/bottom dynamic toolbar implementation.