This is likely a problem with Origins cache. https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/
I'm having the exact same issue. Only difference is that mine was gifted and I have the "New content ready to install" message under play but when I click 'download' for the pack, nothing happens. I've been trying to download for the past hour or so to no avail. I've already uninstalled/reinstalled Origin and tried running as administrator as well as rebooting and nothing's worked.
I am having the same issue mine was gifted and I found the download for it and it shows I have content to install but it won't so I found the download in Origin and when I click on it doesn't download
