I have a project being setup on Jenkins. 

For some reason however, I input my scm details (git in this case but have tried going at it through the multiple scm plugin)
It start to shows the usual errors before I select the credentials, 
select the credentials, and all looks fine
I click apply and save. the saved notification appears.
However if I exit and re-configure the same job, the SCM settings have vanished completely.
(if I run the job it doesn't try to pull and just fails later when it doesn't find my pom.xml)