Hi Karl,
Thanks for the swift reply. Just a bit of context on what we do (the screenshot is below):
We have many branches, but only one to sync. So, depending on what the user selects before building, instead of letting the plugin sync from the depot, we use the CheckOnlyImpl class, and perform the sync ourselves in the build-axis, using the environment variables set-up by the plugin (P4_PORT, P4_CLIENT, etc).
JENKINS_INSTANCE_NAME is defined at Jenkins startup (we build Jenkins as Docker containers on the fly). From what it seems, P4_CLIENT has not the expected value with this version of the plugin, but I might be mistaken... Thanks again.
p4view is correctly defined, using the same environment variables as below and our Perforce depot specifics.

Hi pnobili,
Please get me some screenshots of how the matrix build is defined highlighting the different workspaces so I can try and reproduce this on my test systems.
Regards,
Karl