Cannot Make Changes to Staff

Currently experiencing the exact same issue. I have tried all of those methods as well, to no avail. Network log indicates something is going wrong, but it is not very specific: 

[
    {
        "errors": [
            {
                "message": "Error occurred in one or more of the external services. Check DependencyFailures for specific service error codes",
                "locations": [
                    {
                        "line": 2,
                        "column": 3
                    }
                ],
                "path": [
                    "updateBookingStaffMember"
                ],
                "extensions": {
                    "code": "EXTERNAL_SERVICE_ERROR",
                    "codes": [
                        "EXTERNAL_SERVICE_ERROR",
                        "EXECUTION_ERROR",
                        "EVALUATION",
                        "RPC"
                    ],
                    "data": {
                        "RpcException.StatusCode": "Internal",
                        "RpcException.Status.Detail": "ObjectValidationException: ObjectValidationException: Can\u0027t save invalid object Object Violation. Invalid property = [{ccb88e73-951a-4b10-bb49-e6628b8d8494}:\u0027StaffMembershipStatus\u0027] BookingStaffMembershipStatus. Invalid data for that property = Invalid mailbox session or client or source. Session: SchedulingMailbox, ClientInfoString: Client=CoreStoreObjects;Client=OutlookPlatform. Constraint violated = Microsoft.Exchange.Data.Storage.StaffMembershipStatusConstraint..\r\nService Callstack\r\nMicrosoft.Exchange.Data.Storage.ObjectValidationException: Can\u0027t save invalid object Object Violation. Invalid property = [{ccb88e73-951a-4b10-bb49-e6628b8d8494}:\u0027StaffMembershipStatus\u0027] BookingStaffMembershipStatus. Invalid data for that property = Invalid mailbox session or client or source. Session: SchedulingMailbox, ClientInfoString: Client=CoreStoreObjects;Client=OutlookPlatform. Constraint violated = Microsoft.Exchange.Data.Storage.StaffMembershipStatusConstraint..\r\n   at Microsoft.Exchange.Data.StoreObjects.Validation.Validate(IValidatable validatable, ValidationContext context)\r\n   at Microsoft.Exchange.Data.Storage.CoreItem.InternalFlush(SaveMode saveMode, IEventInvocationScope eventInvocationScope)\r\n   at Microsoft.Exchange.Data.Storage.CoreItem.FlushAndSave(SaveMode saveMode)\r\n   at Microsoft.Exchange.Data.Storage.CoreItem.Save(SaveMode saveMode)\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Transport.StorageCoreObjectBase.SaveAsync(SaveMode storageSaveMode, IReadOnlyCollection\u00601 propsToLoad, Filter conditional, CancellationToken cancellationToken)\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Operations.StorageBaseOperation.Execute_Save_Core(IStorageSaveableBase storageBase, StorageBase_Save_Request request, IProtoMapper protoMapper, ILogger logger)\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Operations.StorageItemOperation.Execute_Save(Referenced\u00601 storageItem, StorageItem_Save_Request request)\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Operations.StorageItemOperation.\u003CInternalStorageObjectExecuteAsync\u003Eb__2_0(Referenced\u00601 referencedObject, Int64 objectHandle)\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Operations.StorageObjectOperation.UsingObjectAsync[T](Int64 objectHandle, Func\u00603 executeAction)\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Operations.StorageItemOperation.InternalStorageObjectExecuteAsync()\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Operations.StorageObjectOperation.InternalTrackedExecuteAsync()"
                    },
                    "InnerMessage": "Grpc:Status(StatusCode=\u0022Internal\u0022, Detail=\u0022ObjectValidationException: ObjectValidationException: Can\u0027t save invalid object Object Violation. Invalid property = [{ccb88e73-951a-4b10-bb49-e6628b8d8494}:\u0027StaffMembershipStatus\u0027] BookingStaffMembershipStatus. Invalid data for that property = Invalid mailbox session or client or source. Session: SchedulingMailbox, ClientInfoString: Client=CoreStoreObjects;Client=OutlookPlatform. Constraint violated = Microsoft.Exchange.Data.Storage.StaffMembershipStatusConstraint..\r\nService Callstack\r\nMicrosoft.Exchange.Data.Storage.ObjectValidationException: Can\u0027t save invalid object Object Violation. Invalid property = [{ccb88e73-951a-4b10-bb49-e6628b8d8494}:\u0027StaffMembershipStatus\u0027] BookingStaffMembershipStatus. Invalid data for that property = Invalid mailbox session or client or source. Session: SchedulingMailbox, ClientInfoString: Client=CoreStoreObjects;Client=OutlookPlatform. Constraint violated = Microsoft.Exchange.Data.Storage.StaffMembershipStatusConstraint..\r\n   at Microsoft.Exchange.Data.StoreObjects.Validation.Validate(IValidatable validatable, ValidationContext context)\r\n   at Microsoft.Exchange.Data.Storage.CoreItem.InternalFlush(SaveMode saveMode, IEventInvocationScope eventInvocationScope)\r\n   at Microsoft.Exchange.Data.Storage.CoreItem.FlushAndSave(SaveMode saveMode)\r\n   at Microsoft.Exchange.Data.Storage.CoreItem.Save(SaveMode saveMode)\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Transport.StorageCoreObjectBase.SaveAsync(SaveMode storageSaveMode, IReadOnlyCollection\u00601 propsToLoad, Filter conditional, CancellationToken cancellationToken)\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Operations.StorageBaseOperation.Execute_Save_Core(IStorageSaveableBase storageBase, StorageBase_Save_Request request, IProtoMapper protoMapper, ILogger logger)\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Operations.StorageItemOperation.Execute_Save(Referenced\u00601 storageItem, StorageItem_Save_Request request)\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Operations.StorageItemOperation.\u003CInternalStorageObjectExecuteAsync\u003Eb__2_0(Referenced\u00601 referencedObject, Int64 objectHandle)\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Operations.StorageObjectOperation.UsingObjectAsync[T](Int64 objectHandle, Func\u00603 executeAction)\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Operations.StorageItemOperation.InternalStorageObjectExecuteAsync()\r\n   at Microsoft.Exchange.CoreStoreObjects.ItemEndpointService.Operations.StorageObjectOperation.InternalTrackedExecuteAsync()\u0022)"
                }
            }
        ],
        "data": {
            "updateBookingStaffMember": null
        },
        "extensions": {
            "X-BackendServiceLatencies": {
                "BookingsService": {
                    "X-Total-Latency": 394,
                    "X-BackendLatency": 359
                },
                "BookingsService.UpdateStaffMember": {
                    "X-Total-Latency": 394,
                    "X-BackendLatency": 359
                }
            },
            "tracing": {
                "version": 1,
                "startTime": "2024-12-09T16:24:22.913283Z",
                "endTime": "2024-12-09T16:24:23.3140765Z",
                "duration": 400793500,
                "parsing": {
                    "startOffset": 900,
                    "duration": 57800
                },
                "validation": {
                    "startOffset": 60500,
                    "duration": 986100
                },
                "execution": {
                    "resolvers": []
                }
            }
        }
    }
]