Hibernate Search allows to mark property and getter of field at once This brings strange behavior of system and errors (for example with highlighter). I think HS should throw an exception at this situation

It is up to you to place the annotations consistently. Generally it is recommended to consistently place them either on fields (for fields access) or on properties (for method access). The same applies for things like JPA or Bean Validation.
On the other hand, there are border cases where it might make sense (or you have to) to mix the annotation approach. Throwing an exception seems to be too strong.
You can open a Jira issue for Search and see what happens.

--Hardy