Swiping to close the tabs list causes its background to animate to full size

Steps to reproduce:

Expected behavior:
The background should not animate at all.

Orion, OS version; hardware type:
Orion 1.0.3.102-beta (WebKit 8612.4.2.0.1), iOS 15.3 (19D5026g), iPhone SE (Model A1662)

Image/Video: