Our P4 Server is configured to require tickets authentication and while the plugin uses tickets in almost all cases that is not true for the new "Quick Clean" option.

Excerpt from logs:

...
[Project] $ /usr/local/bin/p4 -d /Users/Shared/Jenkins/workspace/Project -x - have
Workspace is clean.
Restoring changed and deleted files...
[Project] $ /usr/local/bin/p4 -d /Users/Shared/Jenkins/workspace/Project diff -se
[Project] $ /usr/local/bin/p4 -d /Users/Shared/Jenkins/workspace/Project -x - sync -f
Password not allowed at this server security level, use 'p4 login'.
[Project] $ /usr/local/bin/p4 -d /Users/Shared/Jenkins/workspace/Project -x - sync -f
[Project] $ /usr/local/bin/p4 -d /Users/Shared/Jenkins/workspace/Project diff -sd
Password not allowed at this server security level, use 'p4 login'.
Files restored.
Clean complete, took 43767 ms.
...