webMethods Knowlegebase : searchTask not working with term #{currentTask.taskInfo.acceptedByList} (1806744)

Problem

When searching for the task instances accepted by a particular user, using WmTaskClient/pub.task.taskclient:searchTasks passing Terms:

Fields[0] #{currentTask.taskInfo.acceptedByList}

Operator =

Value User

The search returns no results even if the user has tasks accepted.

The log shows an invalid SQL:

2021-02-11 18:38:00 CET (c.w.c.s.r.r.s.Axis1CommandServlet:INFO) [qtp36097433-98][[WS:4]] [[WS:4]] - Request [13ahjwb6fx8frnbwm1i9d1u63:administrator] http://172.26.111.197:8585/services/bizPolicy/task (POST)

2021-02-11 18:38:00 CET (c.w.p.p.w.c.w.SearchTasksWS:DEBUG) [qtp36097433-98][[WS:4]] [[WS:4]] - Created command bean com.webmethods.portal.bizPolicy.command.task.webservice.SearchTasksWS$SearchTasksCommandBean: {includeTaskData=false, taskSearchQuery={doNotShowAcceptedByOthers=false, maxResults=200, showNonActiveTasks=false, terms=[{_operator==, caseInsensitive=false, fields=[#{currentTask.taskInfo.acceptedByList}], matchedValue=false, value=Administrator}]}, user=Administrator, userTasks=false}

2021-02-11 18:38:00 CET (t.TaskMechanics:DEBUG) [TE Inbox Searches pool-6-thread-1][[WS:4]] [[WS:4]] - Query All Tasks Task Search Query [max:200][user:administrator] searchTerms: {#{currentTask.taskInfo.acceptedByList} = Administrator}

2021-02-11 18:38:00 CET (c.w.p.s.t.TaskIndexEngineFactory:DEBUG) [TE Inbox Searches pool-6-thread-1][[WS:4]] [[WS:4]] - Obtaining a task index engine of type db

2021-02-11 18:38:00 CET (c.w.p.s.t.i.TaskDBIndexManager:DEBUG) [TE Inbox Searches pool-6-thread-1][[WS:4]] [[WS:4]] - Task search DB mode - search context : SearchContext [values={SearchKey [id=te_lazy_fetch, type=class java.lang.Boolean]=true}]

2021-02-11 18:38:00 CET (c.w.p.s.s.r.b.TaskSearchAll:DEBUG) [TE Inbox Searches pool-6-thread-1][[WS:4]] [[WS:4]] - TaskSearchAll: sql = [SELECT T.TASK_ID FROM T_TASK T WHERE (((',' || T.ACCEPTED_BY || ',' in (?)))) ORDER BY T.TASK_ID DESC]; parameters = [[%,2656,%]];

2021-02-11 18:38:00 CET (t.TaskMechanics:DEBUG) [TE Inbox Searches pool-6-thread-1][[WS:4]] [[WS:4]] - Task Query returning: 0 records completed in: 18

2021-02-11 18:38:00 CET (c.w.c.s.r.r.s.Axis1CommandServlet:INFO) [qtp36097433-98][[WS:4]] [[WS:4]] - WebService Request: /bizPolicy/task completed in 55