pg12b1 and version sorting

I'm wondering how versioning on PGDG RPMs is intended to work.
Yum seems to thinks that the "nightly builds" are of higher version number than
beta.

[pryzbyj@dev ~]$ yum list --enablerepo='pgdg12-updates-testing' --showdu postgresql12
...
Installed Packages
postgresql12.x86_64                                                         12.0-devel_20190502_1PGDG.rhel7
                                           @pgdg12-updates-testing
 
Available Packages
postgresql12.x86_64                                                         12beta1-1PGDG.rhel7
                                           pgdg12-updates-testing 
 

[pryzbyj@dev ~]$ sudo yum --enablerepo=pgdg12-updates-testing install postgresql12{-server,-debuginfo,-contrib}
#12beta1-1PGDG.rhel7.x86_64
Package matching postgresql12-server-12beta1-1PGDG.rhel7.x86_64 already installed. Checking for update.
Package matching postgresql12-debuginfo-12beta1-1PGDG.rhel7.x86_64 already installed. Checking for update.
Package matching postgresql12-contrib-12beta1-1PGDG.rhel7.x86_64 already installed. Checking for update.
Nothing to do

I made it work like this:
[pryzbyj@dev ~]$ sudo yum --enablerepo=pgdg12-updates-testing downgrade
postgresql12{,-libs,-server,-debuginfo,-contrib}-12beta1-1PGDG.rhel7.x86_64

..which seems to prove that's what's going on.

I recall that debian handles that using "~", like 12~beta1.

At least, it should be called 12devel and 12beta1 for consistency?  Or
12.0devel and 12.0beta1.

Justin