Error TF282808 'TaskNotFound' error after admin restore on Project Server

Question

We have an integration between TFS 2012 and Project Server 2010 (SP2, with CU).
After an administrative restore of a project on Project server, the workitems that were added to TFS after the point of the backup now fail to synchronise with the following error in the workitem history:
TF282808: An error occurred when sending status update to Project Server during
synchronization. Returned error code: "TaskNotFound". Contact your Project
Server administrator and report the error code.
Workitems that were present before the time of backup sync normally. Workitems that were added after the restore also function normally. It appears as if the sync does not understand that an item from TFS that synced in the past can be new on Project Server
(due to the restore).
I have already tried deleting the webcache on the SharePoint server (C:\ProgramData\Microsoft\Team Foundation\Web Access\Cache_v11.0.xxx) followed by an IISReset.

Answer 1

Hi guys, I am getting this too. 
I have this for several PBI in one team site, and this came out of nowhere. 
TF282808: An error occurred when sending status update to Project Server during synchronization. Returned error code: "TaskNotFound". Contact your Project Server administrator and report the error code.
I also get this when I try to publish the project Ms Project PRO
TF80070: Team Foundation encountered an error while performing the operation. It is recommended that you save your work and restart the application.
This is the tfs_msproject log
Exception:  {
Exception Message: Värde får inte vara null.
Parameternamn: key (type ArgumentNullException)
Exception Stack Trace:    vid System.Collections.Generic.Dictionary`2.FindEntry(TKey key)
   vid Microsoft.TeamFoundation.OfficeIntegration.Client.ProjectAllowedValues.GetMappingOfValuesToIndex(PjCustomField pjCustomField)
   vid Microsoft.TeamFoundation.OfficeIntegration.Client.ProjectServerIntegration.WorkItemTypeFieldManager.SetupWorkItemTypeField(Project project)
   vid Microsoft.TeamFoundation.OfficeIntegration.Client.ProjectServerIntegration.PrePublishValidationManager.Validate(Project project)
   vid Microsoft.TeamFoundation.OfficeIntegration.Client.ProjectServerIntegration.ProjectServerIntegrationAddIn.OnProjectBeforePublish(Project project, Boolean& cancel)
WINPROJ.EXE Error: 0 : [Error, PID 3844, TID 8296, 2014/02/28 11:56:43.233, 8009313 ms, General] TF80070: Team Foundation encountered an error while performing the operation. It is recommended that you save your work and restart the application.
WINPROJ.EXE Error: 0 : [Error, PID 3844, TID 8296, 2014/02/28 11:56:46.016, 8012096 ms, General] UIHost.ShowMessageBox: result=OK caption='Microsoft Office Project' text='TF80070: Team Foundation encountered an error while performing the operation. It is recommended
that you save your work and restart the application.'
WINPROJ.EXE Information: 0 : [Info, PID 3844, TID 8296, 2014/02/28 11:56:46.073, 8012153 ms, General] Whole publish-to-tfs tree validation!