I have a job with a random string parameter using SVN. I copied that job. The new job kept queuing up new builds for every SCM poll even though no changes had been made to the repository. The output messages said:

Job console output:
No revision recorded for https://<myrepositoryhere> in the previous build

SVN polling log:
Workspace doesn't contain https://<myrepositoryhere>. Need a new build.

I removed the random string parameter from the new job and the problem disappeared.