Full text index is not updated field update

On latest version (3.4.1) seems that when i change the value of text indexed field, the old value is not removed from the index. So using Filters.text operator i get the document for the old and new value.

Reproduce:

1. create Text index on a field
2. insert document with text index field
3. search document with Filters.text() -> Works OK
4. update document, removing the text from the indexed field, so now 
5. search document with Filters.text() -> keeps returning the document.

Thanks