task related to timesheet entries

i have the task TS 20000460 which is relateed to time sheet entries with the default rule 00000157 for determining the superior positon and the custom user exit

(cats0008) for determining the approver the task is set in the data entry profile

and everything is fine in the production environment but suddenly we get a issue from the end user saying that the notification to the managers not being sent what could be the probale reason

RH_ACT_LEADING_POSITION is the Fm used in the rule

thanks in advance