Stable update site (1) seems to be not updated to 10.3. They contain text "Latest Build: 10.2.0.GA" and links to Update site zip, Target platform zip, etc. are pointing to 10.2.

(1) https://devstudio.redhat.com/10.0/stable/updates/

Problem is probably only in html page, because when I try to install BYOE from (1) then I see that update site contains 10.3.

The central and early access folders for 10.3.0.GA are missing in [1] and [2].
[1] https://devstudio.redhat.com/10.0/stable/updates/discovery.central/
[2] https://devstudio.redhat.com/10.0/stable/updates/discovery.earlyaccess/