webMethods Knowlegebase : "Failed execute SQL query" when sorting TLM according to "Assigned To" on PosgreSQL DB (1806466)

Problem

On MWS Task List Management , when Customer tries to sort the list of the tasks by "Assigned To", a PosgreSQL error is raised in log:

(c.w.p.s.s.r.b.TaskSearchFromInboxesPaged:WARN) [qtp157478455-1685][ [RID:2339]] [ [RID:2339]] - Failed execute SQL query: SELECT * FROM (SELECT T.CREATED_DATE, T.LAST_UPDATED_DATE MODIFIED, T.TASK_ID TASK_THING_ID, T.TASK_DEFINITION_ID,T.STATUS, T.LAST_UPDATED_BY, T.LAST_UPDATED_DATE, T.EXPIRE_DATE, T.VERSION_NUMBER, T.PRIORITY, T.ACCEPTED_BY, T.LAST_ACCEPTED_BY, T.LAST_ACCEPTED_DATE, T.ASSIGNED_TO, T.DELEGATED_TO, T.DELEGATED_FROM, T.PROCESSED_RULES, T.PENDING_UPDATES, T.PRT_PROCESS_INSTANCE_ID, T.PRT_PROCESS_MODEL_ID, T.PRT_PROCESS_MODEL_VERSION, T.PRT_STEP_ID, T.PRT_PROCESS_ITERATION, T.PRT_STEP_ITERATION, T.PRT_AUDIT_CONTEXT, T.CUSTOM_TASK_ID, T.ATTRIBUTES, T.ERROR_CODE, T.ERROR_MESSAGE, T.PARENT_TASK_ID, T.COLLAB_PROCESS_ID, T.COLLAB_STEP_ID, T.TASK_ID, T.TASK_NAME, T.TASK_DESCRIPTION, '' IDLANG, 0 ID1, 0 ID2, 0 ID3, 0 ID4, T.TASK_ID THINGID, 57 THINGTYPE, 51 THINGXTYPE, 0 THINGVERSION, 0 ISTHINGACTIVE, 0 ISTHINGDELETED, 0 ID5, 0 OWNERXTYPE, T.CREATED_BY OWNERID, 0 OWNERVERSION, 0 ISOWNERACTIVE, 0 ISOWNERDELETED, 0 STYLEXTYPE, 0 STYLEID, T.CONTRIBUTED_BY, T.CHILD_TASK_COUNT, T.IS_MANDATORY, T.TASK_SCHEDULE_DATE, T.IS_VOTABLE, T.TASK_VOTING_TABLE, T.PRT_ROOT_PROCESS_INSTANCE_ID, ROW_NUMBER() OVER(ORDER BY (SELECT N.ITEMNAME FROM TBLTHINGNAME N WHERE N.IDTHING = (CASE STRPOS(SUBSTR(',T.ASSIGNED_TO),') WHEN 0 THEN T.ASSIGNED_TO ELSE LEFT(T.ASSIGNED_TO, STRPOS(SUBSTR(',T.ASSIGNED_TO),') - 1) END)) ASC) R FROM T_TASK T INNER JOIN (SELECT DISTINCT TASK_ID FROM T_TASK_INBOX TI WHERE (((TI.SOURCE_ID in )) AND ((TI.TYPE in (?,?))))) TI ON TI.TASK_ID = T.TASK_ID LEFT JOIN (SELECT DISTINCT TASKID FROM TBLTASKVOTE TV WHERE (((TV.USERID in ))) ) TV ON T.TASK_ID = TV.TASKID LEFT OUTER JOIN TBLTHINGNAME N ON N.IDTHING = (CASE STRPOS(SUBSTR(',T.ASSIGNED_TO),') WHEN 0 THEN T.ASSIGNED_TO ELSE LEFT(T.ASSIGNED_TO, STRPOS(SUBSTR(',T.ASSIGNED_TO),') - 1) END) WHERE (((',' || T.ASSIGNED_TO || ',' like ?))) AND TV.TASKID IS NULL) S WHERE R BETWEEN ? AND ?

(j.e.r.w.j.application:ERROR) [qtp157478455-1685][ [RID:2339]] [ [RID:2339]] - Error Rendering View[/TlmSearchResults/view.xhtml]

com.webmethods.caf.faces.data.ContentProviderException: com.webmethods.caf.faces.data.ContentProviderException: com.webmethods.portal.bizPolicy.BizException: [POP.001.0002] A "{0}" occurred with the Message "{1}"

at com.webmethods.caf.faces.data.task.impl.TaskIndexedSearchContentProvider.refreshPage(TaskIndexedSearchContentProvider.java:300) ~[com.webmethods.caf.shared.bpm_10.5.0.0008-0111.jar:10.5.0.0008-0111]

at com.webmethods.caf.faces.data.object.PageableTableContentProvider.callPageService(PageableTableContentProvider.java:254) ~[com.webmethods.caf.shared.jsf_10.5.0.0008-0111.jar:10.5.0.0008-0111]

at com.webmethods.caf.faces.data.object.PageableTableContentProvider.isRowAvailable(PageableTableContentProvider.java:226) ~[com.webmethods.caf.shared.jsf_10.5.0.0008-0111.jar:10.5.0.0008-0111]

at com.webmethods.caf.faces.component.table.html.DataTable.isRowAvailable(DataTable.java:203) ~[com.webmethods.caf.shared.jsf_10.5.0.0008-0111.jar:10.5.0.0008-0111]

at com.webmethods.caf.faces.component.table.html.DataTable.setRowIndex(DataTable.java:378) ~[com.webmethods.caf.shared.jsf_10.5.0.0008-0111.jar:10.5.0.0008-0111]

at com.webmethods.caf.faces.render.html.table.TableRenderer.encodeChildren(TableRenderer.java:133) ~[com.webmethods.caf.shared.jsf_10.5.0.0008-0111.jar:10.5.0.0008-0111]

at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:889) ~[org.glassfish.javax.faces_2.2.10.jar:2.2.10]

at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856) ~[org.glassfish.javax.faces_2.2.10.jar:2.2.10]

?

In addition, red error message appear on MWS UI