Yep - having tracked this down, it looks like this will impact some of the addons that were originally stored in OHM as a "link" rather than a file. The importer preserved the link data, but didn't create the addon entry as a "link" type, so the system doesn't know how to handle it.
I can fix these, but it's a manual process, so I'll fix them if you let me know about specific ones that don't work, here.