When this method is called from the visitPrepareCommand method, we indeed pass the previous value found just before the call in the cache. 
But after, when the same method is called from the visitRemoveCommand we passe the rv parameter. Which is the Remove Command perfom method answer.

So, having a look to the RemoveCommand, I can see sometimes we indeed return the prev value. But it might happen depending to return a boolean instead. 

remove("key", "value")cache2.remove("newGoat");

LOGS
Thread => 79
ctx.getOrigin() => ClusteredCacheWithElasticsearchIndexManagerIT-NodeA-15125
valueRemoved => Person{name='newGoat', blurb='eats something', age=42, dateOfGraduation=null}
Thread => 38
ctx.getOrigin() => ClusteredCacheWithElasticsearchIndexManagerIT-NodeB-23459
valueRemoved => Person{name='newGoat', blurb='eats something', age=42, dateOfGraduation=null}
Thread => 47
ctx.getOrigin() => null
valueRemoved => Person{name='newGoat', blurb='eats something', age=42, dateOfGraduation=null}
removeFromIndexes method is called !!!

But if we call remove with specific value, the method removeFromIndexes is never called.
cache2.remove("newGoat", person4);
LOGS
Thread => 79
ctx.getOrigin() => ClusteredCacheWithElasticsearchIndexManagerIT-NodeA-22063
valueRemoved => true
Thread => 38
ctx.getOrigin() => ClusteredCacheWithElasticsearchIndexManagerIT-NodeB-47249
valueRemoved => true
Thread => 47
ctx.getOrigin() => null
valueRemoved => true

But in both cases the remove seems to be working, because this assertions work.
found = searchManager.<Person>getQuery(allQuery, Person.class).list();

assertEquals(0, found.size());

I'm a bit confused about all this, but we can chat o IRC or bluejeans. It might be some bugs concerning this interceptor, Radim has already opened an issue on this matter.
Katia
return invokeNextThenAccept(ctx, command, (rCtx, rCommand, rv) -> processComputeCommand(((ComputeCommand) rCommand), rCtx, stateBeforeCompute, null));

Gustavo
public void testToto() throws Exception {
    SearchManager searchManager = Search.getSearchManager(cache2);
    QueryBuilder queryBuilder = searchManager
          .buildQueryBuilderForClass(Person.class)
          .get();
    Query allQuery = queryBuilder.all().createQuery();

    String key = "newGoat";
    Person person4 = new Person(key, "eats something", 42);

    cache2.putIfAbsent(key, person4);
    StaticTestingErrorHandler.assertAllGood(cache1, cache2);

    List<Person> found = searchManager.<Person>getQuery(allQuery, Person.class).list();
    assertEquals(1, found.size());
    assertTrue(found.contains(person4));
}