Comment # 9 on bug 1106577 from Joe Morris

I doubt it is a timing thing, mainly because it is so reproducable. I don't use
plymouth and have splash=verbose in my kernel command line. I haven't tried
with plymouth enabled, except of course the Live KDE DVD.

I did a new install to a HD in a USB 3 external case, partitioned similarly to
my main HD (i.e. GPT, 4 primary partitions, 1=EFI, 2 & 3 is root and home
(ext4), and 4 is swap. After installing, so far, it boots fine with the same
packages and hardware, except my original system has over 6000 packages and the
new system only ~2500. I plan to install packages into this new system to match
my original system until I can track down the problem package/program. I
started last night, and noticed the new system did not have acpid installed,
and uninstalling it on my main system actually allowed 4.18.5 to boot normally
once. I thought I had it, but the next boot attempt was the same problem.
Hopefully I can install in small coherent enough groups to track down the
problem in my new "test" system. Certainly has been hard to troubleshoot.