Stored Procedure causing Assertion Fail on 7.12 Solaris 2.4

Has anyone experienced a stored procedure causing an Assertion Fail of the engine? We began experiencing this problem recently when we began calling the procedures from a new main stored procedure instead of a PowerBuilder App starting a series of procedures individually. The volume of data that gets processed varies depending on the current engine load, and when we attempt to recreate the problem on another instance, the procedure runs without error. We have experienced severe memory consumption problems while running any stored procedure. It seems a session will not release the allocated memory after the procedure has completed. Any Ideas????