I have a job that gathers a lot of different components from Perforce and we recently added a few new lines. After the job built once we attemt to go back into the config screen for the job and the settings come up but we get a "ERROR" just below the mapping that once you click on it it shows a 404 error and after that the user is logged out of Jenkins. If I delete the project mapping from the config.xml and reload from the disk the job is editable again until the next build. I have tried to use the clientspec feature but this also adds back in the <projectPath> key in the config.xml and again the error reoccurs after the first build. Right now the only work around is to modify the job file manually with a text editor. The jobs seem to build just fine. I have attached a job config file to show the issue. If I reduce the mapping down to 2974 bytes the error goes away and does not seem to return. My feeling is it is in the parser of the mapping, but that is a guess. For user login control we currently are using "Project-based Matrix Authorization Strategy" with "Jenkins's own user database".