Ok, I thought I would do a bit of checking on my Mac also. According to Safari I was running version 13.0.2
the latest offering. I looked in the Software> Installations section and it was not listed, odd.
I then checked for available updates and it said 13.0.2 was available for download, strange. So I downloaded it and it installed.
It is now listed as installed in the System Report> Software> Installations list.
So I cannot give you a definitive answer as to why that would be, perhaps there was a revision that they don't want to admit to, but remember it is not you that is going mad it is everyone else.