Please check the program code in the transaction SE24.
If the code is available, delete the GW cache by execution following transactions.
/IWFND/CACHE_CLEANUP in Gateway.
/IWBEP/CACHE_CLEANUP in SRM.
Model Provider Class: /GBSRM/CL_APV_SC_MDP, Methof DEFINE
...
* Define Entities
define_entity_workflowtask( ).
...
Data Provider Class: /GBSRM/CL_APV_SC_RDP, Method GET_ENTITYSET
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CASE iv_entity_name.
WHEN 'WorkflowTask'.
...