The download page says the DVD image iso size is supposed to be 4.7 GB, but the iso I downloaded is only 3.6 GB. Is the download page wrong, or is something wrong with the iso I downloaded? (The checksum matches.)
If the checksum matches, you are fine. I am seeing a length of 3917479936 for the iso.
The 4.7 is the max capacity of standard DVDs (depending on the type of DVD).
I submitted https://bugzilla.opensuse.org/show_bug.cgi?id=1094792, although I am not exactly sure which component is the right one (and even whether this should go via bugzilla or not).
I actually submitted an email to the website and they generated a ticket:
tickets #36532: New Leap Release
https://progress.opensuse.org/issues/36532