I have a job setup that sets a custom workspace, the name of which is dependent on job parameters:

Use custom workspace:

/jenkins/slave/workspace/${JOB_NAME}${DEPOT}${PLATFORM}

where DEPOT and PLATFORM are choice parameters.

This job is often run twice in succession, once for one value of PLATFORM and right after for another value.

When the job is run and the "Delete workspace before build starts" box is checked, it deletes the workspace from the previous iteration of the job, rather than the previous iteration of the job that had the same parameters.

Example:

if the job is being run with a workspace of:

/jenkins/slave/workspace/My_Job_dev_ios

instead of deleting that directory so it's fresh for that iteration, it deletes

/jenkins/slave/workspace/My_Job_dev_android

as that's what the previous build had as parameters.

I verified this behavior by looking at the folders on the build node (jobs were executing consistently on the same node) and see what was deleted.