I was playing around with some modules and doing /dev/build/?flush=1 when I noticed "An error has occured" at the very bottom of of the report under "Creating Database records".
So I slipped the site into DevMode and the error changed to a simple one line error that says:
I can't handle sub-URLs of a DevelopmentAdmin object.
I tried deleting modules to no avail, until I decided to install a fresh copy of 2.3.2 on the same server. Nothing went wrong during installation.
After the fresh install, I did a /dev/build/?flush=1 on the site to test if this message came up again, and it did. I even went as far to delete the cache files in /tmp/ for this site.
Has anyone seen this? Must be a server issue of some sort.