Unfortunately this Jenkins instance did not have any backup so nothing was recovered. I skipped 2.175 and 2.176 and upgraded to 2.177. The good news is the issue with builds automatically restarting and failing after a Jenkins restart is not occurring anymore. The bad news is we probably will never know what happened now It may have been related to JENKINS-57254.
Anyway, I will go ahead and close this Jira since the issue cannot be reproduced anymore. Thanks for looking into this.