This bug was originally reported for ResSim 3.5, and has been investigated but not addressed for 4.0 or 4.1.
Scenario: Occurs when Mod Puls storage-outflow relationship does not start with a zero flow entry
How to Address: provide complete and valid input data.
See the 4.0 notes: ResSim 4.0 Known Issues - Mod Puls Routing Mass Balance Error