Hi Greg,
Hmm, yep I noticed it. It seems on pages that take a bit more time to load (i.e. to fire the DOMContentLoaded event) this effect might be noticeable. I will think about possibly a bit improved sample code in the docs but you can fix the issue in the meantime by adding the collapsed class to your menu tree in the source by default:
<ul id="main-menu" class="sm sm-gjs hidden-print collapsed">
Let me know if you still have any troubles.
Cheers!
