Bug migrating process instance in 6.7.2

**Describe the bug**
Hi!
I’m using flowable 6.7.2 and looks like there’s a problem migrating process instance from one callActivity to another in this version.
Let’s say, I have a simple model like this one:

After starting the process it goes to “call activity 1”. Inside both callActivities there’s just a single user task. So the main process will stop on “call activity 1” and wait for a user task completion.
Now let’s try to migrate process instance from “call activity 1” to “call activity 2” (same model version).

**Expected behavior**
active token will be moved from “call activity 1” to “call activity 2”, subprocess corresponding to “call activity 1” will be deleted and a new subprocess corresponding to “call activity 2” will be started.
Real behavior: no errors, but process instance has no changes after migration.

**Code**
Here’s the code I’m using for migration:

```java
String pid = "4505147";
String definitionId = "test_migration_bug:4:4505206";
ProcessInstanceMigrationBuilder migrationBuilder = processMigrationService.createProcessInstanceMigrationBuilder();
migrationBuilder.migrateToProcessDefinition(definitionId);
ActivityMigrationMapping currentMapping = ActivityMigrationMapping.createMappingFor("Activity_1ik53m0", "Activity_0jpkzf3");
migrationBuilder.addActivityMigrationMapping(currentMapping);
migrationBuilder.migrate(pid);
```

BPMN model:
```xml

Flow_1x3nwgx



Flow_1atp8ps
Flow_0ti4wed



Flow_1x3nwgx
Flow_0lspzco
Flow_0j97xr8


${true}


${false}



Flow_0lspzco
Flow_1atp8ps


Flow_0j97xr8
Flow_0ti4wed

```

**Additional context**
Flowable 6.7.2, PostgreSQL 13.0, Spring Boot.