Regarding A Channing Problem

[Ajay3oodles]

Im working on a VRP dummy project using a custom chaining heuristic. I’m traversing through employees E1, E2, E3 and a NoneEmployee placeholder to assign visits V1, V2, V3, V4, V5, V6.

Currently, if assigning a visit (e.g., V2) to E1 worsens the score, the existing code assigns V2 to NoneEmployee. However, this can cause a problem: V2 might have been a good fit for E2, but since it is already assigned to None, it is no longer considered for E2.

I want a better approach: instead of assigning V2 to NoneEmployee, I want to unassign the visit from the chain, i.e., break it from E1’s chain:

E1 -> V1 -> V2

Set V2.previous = null
Set V2.employeeShift = null
Update V1.nextVOB = null

However, when I try this, I get the following exception:

java.lang.IllegalStateException: The entity ([Visit-6ad18b4a-d911-49fe-a480-7c6601f23f40]) has a variable (previousVisitOrEmployee) with value (Employee{startDate=2025-10-24 07:00:00.0, endDate=2025-10-24 13:00:00.0, employee=Bethany McC, travelType=Car-Company}) which has a sourceVariableName variable (nextVisit) with a value (null) which is not that entity.
Verify the consistency of your input problem for that sourceVariableName variable.

I’m looking for guidance on how to safely unassign a visit from a chained planning variable so that it can be reassigned to other employees without breaking the chain.