Off canvas menu animates during page transition sometimes

[dr-starchildren]

Setup

• Browsers and versions: Firefox 75, 74
• MediaWiki version: 1.3.2
• Database version:
• PHP version: 7
• Pivot version: 2.1.1
• Extension version (if connected to the issue):

Issue

When transitioning pages or when initially opening a page, sometimes the left and right menus will animate their closing effect, moving off screen. This will happen inconsistently, but most often when initially visiting the page. I haven't found a way to consistently make it happen, but it does occur roughly 10 - 20% of the time when moving pages.

The problem doesn't occur in Chrome, so this might be an issue with the foundation.css and Mozilla specific commands.