One difference I have noted is that the svn url where the variables are not found contains lower/upper case characters.  This used to work in previous version of the subversion plug-in.  I do not recall which version.

The other difference I see is that the repository base URL is longer in the cases where the variables are not defined

I was trying to troubleshoot and I made the URL same length with no uppercases.  Same problem.  Made URL shorter (sort of normal length). Same problem.  I reverted to original URL and the problem disappeared!  The SVN_URL and SVN_REVISION appeared.  What can be the cause of this behaviour?  Is there some caching done somewhere?  In the past, I had tried to remove the job from Jenkins and recreated it and the problem was still there.  One last note to point, I have been using JOB DSL to create those jobs.  Don't know if that is a factor.

Last but not least, since this was unassigned from someone a few minutes after creating, will anyone look into this?

Update, I recreated the job using job DSL and I get the error again using the same repository base url.  I still get the error if I delete the job and recreate it manually, even using a different name.  The job is created inside a folder if that is something that matters.

I found out what was going on.  I had two consecutive / in the repository base URL.  Once I removed it, everything works.