I happen to experience the same as previous users. Awstats were generating reports correctly until one day when it stopped. The problem was a file permission on logs. (same as here in 2011 and here in 2023).
This was already reported but I would like to reopen the topic to try to figure out what is the cause of this. I don’t think I made any change on Awstat at the time.
As far as I know, that’s how log ownership is and has been for many years. None of my systems have ownership like you’re seeing, they are all owned by the domain owner user and have group ownership of the Apache user (www-data on Debian/Ubuntu, apache on EL), and I’m not sure why that would have changed on your system.
I don’t actually know how/where permissions get set, as it’s not in the Apache config. There may be an option in Virtualmin that effects this that you’ve altered, but I can’t find it, thus far.