The site we encountered this on had done an early upgrade to 5.10 so it was behind in some package versions.
I upgraded to 5.10.1b3 and it does still create the folder bootstrap/bootstrap@5.3.2 by visiting the acs-admin/package/openacs-bootstrap5-theme/ page.
However since it no longer is creating the dist folder underneath that location the problem no longer occurs.
Thanks for the response.
