Out of balance Cash Flow with variance found in FCCS_Mvmts_Subtotal

Summary: We are trying to understand why our Cash Flow is out of balance (Total Cash Flow does not equal Cash Change) by movement in FX in isolated instances.

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We are trying to utilize the out-of-the-box cash flow functionality, and we are starting off with a balanced trial balance with all accounts mapped to a movement member in the movement primary hierarchy. Almost all items can be tied out, but the total cash flow is out of balance by amounts found in parent currency that are out of balance at FCCS_Mvmts_Subtotal, the offset found in sibling FCCS_Mvmts_FX_Total. We believe the source of the issue is for historical override accounts in the few places we have this issue. Has anyone worked through this issue before?