We have detected a few time that the unshelve fails for various reasons:
Below is one such example, the p4 plugin should throw an error so it is obvious to the Jenkins job that there was an scm errom.

p4 unshelve -f -s141408 -cdefault

Librarian checkout /p4/mlb.1/depots/atf/int_mlb/jenkins_batch/atf_l1phy_anritsurtd_build_step.bat failed.
Error opening librarian file /p4/mlb.1/depots/atf/int_mlb/jenkins_batch/atf_l1phy_anritsurtd_build_step.bat revision 1.141408.
open for read: /p4/mlb.1/depots/atf/int_mlb/jenkins_batch/atf_l1phy_anritsurtd_build_step.bat,d/1.141408.gz: No such file or directory