The Grinder Jenkins plugin only reloads graphs if the underlying project has changed:

https://github.com/jenkinsci/grinder-plugin/blob/master/src/main/java/hudson/plugins/grinder/AbstractGrinderAction.java#L29

In my use case the performance tests are initiated by a separate project from the actual code and until we integrate continuous deployment the tests are run by users on demand. Consequently, the project has not changed and the graphs are not updated.

In order for the graphs to be updated I added a configuration switch to the plugin to always update the graphs. I've never worked in the codebase (Jenkins or Grinder) so I may have misunderstood the model; but this did solve our problem.

I have included a screenshot, diff and compiled HPI file. The results were tested under Jenkins 1.503.