[aria-hidden="true"] is present on the document <body>
This is not a problem with native Webflow.
Using CSS to hide elements (such as a mobile menu) does NOT need ARIA.
If you create a <button> using ARIA roles, take care with this audit criteria.
Google Lighthouse says
Users of screen readers and other assistive technologies need information about the behavior and purpose of controls on your web page. Built-in HTML controls like buttons and radio groups come with that information built in. For custom controls you create, however, you must provide the information with ARIA roles and attributes. (Learn more in the Introduction to ARIA.)
Screen readers and other assistive technologies don't announce content that's marked as hidden. Applying the aria-hidden="true" attribute to your <body> element hides your entire web page from assistive technology users.