The problem is when you want to have a Business Process Flow (BPF) that changes automatically when a user changes a field, but that process flow is only changing to that user and not to the others.
When user1 changes the field, he can see the BPF changing after the reload of the form. When user2 looks at the same record, he can’t see the BPF changed.
This happens because the BPF’s in Dynamics 365 allows multiple processes to run concurrently against the same record and the process that is running for a user might not be the same to the other user.
To have a workaround that works, it is necessary to implement a JScript OnLoad calling that will set the active process in the record to the one that the user wants, for that it can be used Xrm.Page.data.process.setActiveProcess/setActiveProcessInstance.
If you want to know more about the new BPF and how it works, take a look at this post.
Hope this helps.