Error "Content object "xxx.pdf" in the document "xxx.drw" was not uploaded to the server vault" during checkin from Workspace in Windchill PDMLink

• Cannot check in a drawing when its attachment has been deleted from commonspace while still shows in workspace copy information page
• Check in will fail with error when custom workflow deletes the drawing from commonspace without checking out the drawing, but the attachment still shows in workspace copy of the drawing
• Conflict error in Event Management:

Conflict Description:
Content object "xxx.pdf" in the document "yyy.drw" was not uploaded to the server vault.

• Error in Method Server Logs:

ERROR  com.ptc.windchill.uwgm.proesrv.StandardRequestDispatcher xxx - StandardRequestDispatcher.dispatchRequest :: Unexpected failure(s) com.ptc.windchill.uwgm.common.conflict.UwgmErrorException: com.ptc.windchill.uwgm.common.conflict.UwgmErrorException:
Content object "xxx.pdf" in the document "yyy.drw" was not uploaded to the server vault.

Nested exception is: com.ptc.windchill.uwgm.common.conflict.UwgmErrorException:
Content object "xxx.pdf" in the document "yyy.drw" was not uploaded to the server vault.
	at com.ptc.windchill.uwgm.proesrv.action.UpdateContentAction.updateContents(UpdateContentAction.java:192)
	at com.ptc.windchill.uwgm.proesrv.action.UpdateContentAction.executeAction(UpdateContentAction.java:126)
	at com.ptc.windchill.uwgm.proesrv.action.UwgmAction.execute(UwgmAction.java:84)
	at com.ptc.windchill.uwgm.proesrv.upload.UwgmUploadHelper.updateContents(UwgmUploadHelper.java:257)
	at com.ptc.windchill.uwgm.proesrv.upload.UwgmUploadHelper.upload(UwgmUploadHelper.java:140)
	at com.ptc.windchill.uwgm.proesrv.upload.UwgmUploadHelper.performUploadOperation(UwgmUploadHelper.java:585)
	at com.ptc.windchill.uwgm.proesrv.request.EpmUploadRequest.executeRequest(EpmUploadRequest.java:115)
	at com.ptc.windchill.uwgm.proesrv.StandardRequestDispatcher.dispatchRequest(StandardRequestDispatcher.java:1277)
	at com.ptc.windchill.uwgm.proesrv.StandardRequestDispatcher.scanRequests(StandardRequestDispatcher.java:1014)
	at com.ptc.windchill.uwgm.proesrv.UwgmTransactionExecuterImpl.execute(UwgmTransactionExecuterImpl.java:109)
	at com.ptc.windchill.uwgm.proesrv.UwgmTransactionExecuterImpl.executeTransaction(UwgmTransactionExecuterImpl.java:59)
	at com.ptc.windchill.uwgm.proesrv.ProeService.executeTransaction(ProeService.java:111)
	at com.ptc.windchill.uwgm.proesrv.ProeService.execute(ProeService.java:87)
	at com.ptc.windchill.uwgm.soap.impl.uwgm.BinaryRequestHandler.processRequest(BinaryRequestHandler.java:677)
	at com.ptc.windchill.uwgm.soap.impl.uwgm.BinaryRequestHandler.getCacheDescriptor(BinaryRequestHandler.java:526)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at wt.httpgw.HTTPServer.processRequest(HTTPServer.java:346)    
    ...