Comment 9 for bug 1773045

That fix is great, but not for those going through a new install of 18.04. I had to let the entire installation process finish before I could do anything about those messages at all, and their are dozens of them that go by. Given this is a new problem in this theme in 18.04 (at least as far as I know) and was definitely not present in 16.04, the issue should be addressed to avoid errors during installation of (or upgrade to) 18.04. Your fix can't be made until one of those is done.