Steps to reproduce:
1. Go to a package with a lot of titles (for instance https://folio-testing.aws.indexdata.com/eholdings/packages/28825-12383)
2. Start scrolling the page
At the moment when "Titles" accordion touches the pane header, the scrolling of the package details becomes disabled. Instead, the title list is now scrollable and the "Titles" accordion header becomes sticky.
The switch between "scrolling whole package details page" and "scrolling titles list section only" does not happen immediately. Sometimes a user has to stop scrolling, wait for a half a second, and then scroll again to see that the scroll mode was changed. Also, making mouse moves helps to speed up the process of switching.