Jenkins memory issue after disabling plugin

Recently we upgrade few plugins in jenkins and we suffered from unexpected behaviour .
Because of this we disabled and downgrade some of the plugins .
After this changing we started suffer from memory issue in jenkins.
In few hours of work the jenkins increase is heap to the maximum and jenkins stop response.
We analyzed Jenkins  heap dump ,using "Eclipse Memory Analyzer"  we found the suspect is hudson.diagnosis.OldDataMonitor the description of this object by jenkins javaDoc "Tracks whether any data structure changes were corrected when loading XML, that could be resaved to migrate that data to the new format."
We understood we should clean all jobs config.xml from old data 
Jenkins have feature to do it "Manage Jenkins" --> "Manage Old Data" --> "Discard Old Data"
Jenkins have related bug for this issue
DevOps Architect

DevOps Group