I am using Jenkins 1.475 with the perforce plugin.
I have several jobs using different perforce workspaces and different Jenkins workspaces.
For some reason the build history for each job includes the builds of other jobs. This may be related to JENKINS-11853.
The last failed and last successful builds seem to be determined by build number rather than date.

If you look at the second and third snapshots you can see that Jenkins alternates in its decision over what builds to include in the the history on the left hand side. This may be related or a separate bug.

I have given each job a custom workspace with a unique name to avoid conflicts. Further I have installed the set next build number plugin and given each job a next build number +1000 from the others. This seemed to work until I was forced to restart Jenkins (due to a hardware issue) after which the problem has reoccurred. This scheme would be unviable in general anyway after any one project had more than 1000 builds.

This may be down to a misconfiguration of some kind on my part but it is not at all obvious what is wrong or how to fix it.
A contributing factor could be that some jobs were created by copying existing jobs. Perhaps this caused something to be shared that shouldn't be?