There is no guarantee that you will get the same workspace on a node. It will try, but a workspace can only be in use by 1 job at a time. So if you require a specific workspace, you have a few options:
Define a custom workspace with the ws step. But I think 2 jobs still can't use it at the same time.
Stash/unstash the files you need to persist across nodes or stages
set into a directory outside of the workspace to do what needs to be shared
Use resource locking so that other jobs wait to access the workspace. Still not guaranteed to get the same workspace.
Use resource locking combined with ws to specify a specific workspace and other jobs will wait for access to it.
Specify a custom workspace and don't allow the job to run more than 1 build at a time.