A user of cloudbees-folders-plus (from Jenkins Enterprise) reports that moving a job from folder to Jenkins root is broken with
java.lang.ClassCastException: com.cloudbees.hudson.plugins.folder.relocate.RelocateTask cannot be cast to hudson.model.Job
at jenkins.advancedqueue.PriorityConfiguration.getPriorityInternal(PriorityConfiguration.java:207)
at jenkins.advancedqueue.PriorityConfiguration.getPriority(PriorityConfiguration.java:199)
at jenkins.advancedqueue.sorter.AdvancedQueueSorter.onNewItem(AdvancedQueueSorter.java:111)
at jenkins.advancedqueue.sorter.AdvancedQueueSorter.getCalculatedWeight(AdvancedQueueSorter.java:103)
at jenkins.advancedqueue.sorter.AdvancedQueueSorter.access$000(AdvancedQueueSorter.java:47)
at jenkins.advancedqueue.sorter.AdvancedQueueSorter$2.compare(AdvancedQueueSorter.java:78)
at jenkins.advancedqueue.sorter.AdvancedQueueSorter$2.compare(AdvancedQueueSorter.java:76)
at java.util.TimSort.countRunAndMakeAscending(Unknown Source)
at java.util.TimSort.sort(Unknown Source)
at java.util.TimSort.sort(Unknown Source)
at java.util.Arrays.sort(Unknown Source)
at java.util.Collections.sort(Unknown Source)
at jenkins.advancedqueue.sorter.AdvancedQueueSorter.sortBuildableItems(AdvancedQueueSorter.java:76)
at hudson.model.Queue.maintain(Queue.java:1092)
at hudson.model.Queue$MaintainTask.doRun(Queue.java:2084)
at hudson.triggers.SafeTimerTask.run(SafeTimerTask.java:54)
at java.util.TimerThread.mainLoop(Unknown Source)
at java.util.TimerThread.run(Unknown Source)
Probably other special queue tasks would also be broken by this plugin, which assumes without checking that every Task is a Job.