Was a flow rule updated in such a way that an existing assignment was removed - an assignment at which cases are currently active?
There are 3 ways to deal with this situation:
1) Brute force (not recommended); define a different application, force users to switch back and forth
2) Batch process every case affected by the flow change moving them to a valid assignment. The drawback to this is approach is potential performance impact plus having to take into consideration that the case might be open.
3) Leave the existing assignment in place but disconnect its input connector(s). After all existing cases have moved beyond that assignment, remove it from the flow.
Circumstancing a flow is possible but is overly complex to manage so is also not recommended.
Hard to picture what you are doing. Starting a flow during GetNextWork?
The other arround, you can have GetNextWork automatically invoked during flow processing when not able to reach the next assignment due to security restrictions or the case is resolved. You configure that on the flow rule.
If a case resolves you want it to remove all of its assignments - pxForceCaseClose will do this.
Sounds like you have a complex "skill matching" requirement for Get Next Work. Is that the crux of the issue are experiencing?
No idea why anyone would want to spin off a flow in the process of retrieving work.