In the FA Viewer "Contents of the Collection" accordion has multiple layers of nested accordions. In the accordions with descriptions of physical box and folder details the <ul class="list-unstyled"> contains an <li> with a <button type="button" class="btn btn-warning fa-request fa-requestable-contents">. If there is more than <li> the buttons do not display vertically stacked.
Example:
https://exploreuk.uky.edu/fa/findingaid/?id=xt7r4x54jn8d#fa-heading-ref17

Suggested Fix: