Business Process Flow Error: “Participating entity record of stage: X is not valid” (0x80040216) (Dynamics 365 / Dataverse)

Scenario Working on a custom multi-entity Business Process Flow (Opportunity → Quote) recently, we ran into this error while trying to reactivate the process: The BPF (custom_salesprocess) had already traversed several stages — Generate Opportunity → Qualify → Generate Quote → Initiate Deposit/Bank Guarantee → Sales Completion — before landing on PM Completion, which sits … Continue reading "Business Process Flow Error: “Participating entity record of stage: X is not valid” (0x80040216) (Dynamics 365 / Dataverse)"